Practices to AVOID
1: Do not fail to keep your internet programs and your computer updated!
Many of the updates for both Windows and Windows programs are security updates that your PC needs to stay current in the battle against malware. Don't put your PC and yourself at risk, KEEP IT UPDATED!

2: Do not have more than one active antivirus (AV) program on your PC. Two active AV programs may conflict with one another rendering you defenseless. Use Programs and Features in the Control Panel or Apps and Features in Win 8 or 10 PC Settings to uninstall extra programs you don't want, or need.
    Unactivated Windows Defender in Windows 8 and 10 and/or on-demand virus scanners such as Malwarebytes do not count as active antivirus programs.

3: Do not use unsafe email practices. (Where do I start?)

Programs:
    Old programs such as Windows Mail and Outlook Express seem to invite spam.
    Windows 7 - Windows Live Mail, Yuck!
    Windows 8 Email - "It's too pooped to POP!"
    Use Outlook (if you have Microsoft Office) or Web Mail (Outlook.com, gmail, yahoo mail, etc), or Mozilla Thunderbird desktop email program
Use the latest updated versions of desktop programs, if at all possible for maximum protection.

4: Do not open email attachments you haven't manually scanned with your virus scanner.
However, it has been demonstrated that some malware files fail to be detected by some malware scanners.

5: So, Do not open email attachments you were not expecting, no matter who they appear to be from. Be Safe! JUST DELETE THEM!!

6: Do not respond to spam email messages. Be wary about using using unsubscribe links (just mark message as junk) and never click directly on links in email messages. Again, just delete them!
    If you have won a lottery, a gift certificate, or received an inheritance you should certainly know it, without having some spam email informing you.

7: Never visit questionable websites (ie porn, warez, hacking) However if you must download files from these sites use discretion, scan all downloads with your up-to-date antivirus program as soon as download is complete. If files are compressed, scan again after decompressing or extracting!
    Perhaps you've noticed the Scan command in the context menu when you right-click any file.

8: Do not poke unnecessary holes in your firewall by clicking 'Allow' every time some program requests access to the Internet. When it doubt over whether or not to allow some program, use Google to find out what it is and whether or not it needs access to the Internet. Otherwise, denying access is the safest course of action, since you can always change the rule later if something does not work as you expect.

9: Never download programs and files from questionable sites. Use Filehippo (safe) or search with Google or Yahoo to find out what others are saying about a site before downloading any software or files.

10: It's not a good idea to use file sharing or P2P programs. (Torrent sites are filled with malware.)

11: Do not use pirated programs. You have no idea what the creators have placed into these programs. There are too many free programs available to take such chances. See my Freeware page at http://www.greenthumbnsy.com/freeware.htm

12: Never connect to unknown devices. Don't plug strange USB flash drives into your PC.
If you find a flash drive laying around in a public area just trash it.
Be Wary.
If you found a bottle of aspirin on the floor of a waiting room, would you keep them to take the next time you had a headache? Of course not! There's no telling what could be in those pills. Same with the USB drive. There's no telling what could be on it.
Virus? Ransomware? No telling.
Garbage cans were made for things like this. Better to be safe! Remember. Curiosity Killed the Cat!

13: Never use Registry cleaners or optimizers unless you know EXACTLY what you are doing. No matter what anyone says you cannot magically gain great speed increases from using these programs. Leave the Windows Registry alone until you gain more knowledge about how it works. You can easily render your PC unusable by poking into the Registry.

14: Do not use the same password and/or username for every internet site you login to. If a hacker were to gain access to your username and password for one site then he (or she) would be able to login to any site you use and possibly create enormous problems for you.

15: Don't click on any bogus popup ads - especially if the ad says your PC is infected with a virus. Close the window or turn off the browser. Use Alt+F4 or the Task Manager to close the program or turn off your PC if nothing else works (hold down the power button). It's better to take the time to restart your PC than to take a chance of getting PC malware. At best you'll need to spend your valuable time researching and dealing with the problems or at worst you may need to replace your operating system, potentially losing files and installed programs.

If you think your PC may be infected run your antivirus scanner or Malwarebytes to find out for sure. Don't take chances with your security!!

16: Never provide any passwords or personal information in response to any message, email or a phone call, informing you that your account(s) were hacked or compromised. Deleting all such emails or ending the phone call is the most appropriate response.

17: Both Windows XP and Windows Vista are obsolete!
    If you have an old PC which is still running Windows XP or Vista I strongly advise you NOT to connect it to the internet any longer. Neither Windows XP or Vista are being supported by Microsoft with critical security updates and are vulnerable to malware intrusion and hacking to a much greater degree than later operating systems.

    If you wish to continue using the PC hardware I suggest you replace Windows XP or Windows Vista operating system with a fast and FREE linux operating system such as LXLE, Puppy Linux or Manjaro Linux.

    If you need advice with purchasing a new PC see my page How to buy a "Cheap" PC.

    You should know, if your PC is running Windows 7 it has recently suffered the same fate as Windows XP and Vista. See this Microsoft page for an update on the status of Windows 7. I suggest either installing Windows 10 (if possible) or a FREE and secure Linux operating system such as Ubuntu or Linux Mint if you wish to continue using your old PC hardware.

Things you SHOULD do

1: Topping the list of the things you should do is to create recovery media (DVDs or USB Flash Drive) for your new Windows 10 computer. PC manufacturers typically no longer include recovery disks with new PCs.

    Also, make regular backups of your personal files.
    If your PC's hard drive quits or if Ransomware infects your PC you will be glad you did.
    See my page Backup your PC to learn how.

    Also, if you have a new Windows 10 PC you should download all current Windows Updates to make your new PC as secure as it can be. Go to PC Settings by clicking the gear icon in the Windows 10 start menu, then choose Update and Security and then click the Check for Updates button.
Note: If you have recently updated (or clean installed) Windows 10 you should Check for Updates as soon as possible also.

    Allow Windows Update to download all current updates before you leave PC Settings. Depending on the speed of your internet connection it may take a while to get this done, but your PC will be much more safe and secure if you take the time to get fully updated.

2: Either disable all extensions (browser helper programs) in Internet Explorer or stop using Internet Explorer (probably best). Mozilla's Firefox and Google Chrome are much safer and better alternative Internet Browsers. Even Windows Edge which now comes with Windows 10 is much more secure than the old Internet Explorer.

3: Always have an up-to-date antivirus program running. There is no reason not to have one since it is not necessary to pay for a good antivirus program. (See the Security Programs section of my page Freeware to identify and locate them.)

At least use Windows Defender for Windows 8 or 10. If every PC had a decent security program running many hackers might need to find another line of work.

4: Always have a firewall running. Windows firewall should always be on unless you have a router or gateway that includes a firewall. Note: Running two firewalls may slow your connection speed.

5: Always use Windows Update to download and install all the latest Windows updates, including all security updates, from Microsoft.

6: Always delete all unsolicited emails containing attachments without reading. Curiosity killed the cat. (I know, I mentioned some of these things earlier. But people can't hear it enough. It's important.)

7: It is a good idea to manually scan all email attachments with your antivirus program, regardless of whether it's supposed to be done automatically.

8: Always copy and paste URLs from email messages into your web browser. Don't simply click on them! If they don't look right turn off your browser rather than going to a potentially dangerous site.

9: Always inspect links copied and pasted into your web browser to ensure they don't seem to contain a second/different address.

10: Always backup your data files. In Windows 10 you can go to PC Settings, then Update and Security, then Backup to Backup using file history. (you'll likely need an external hardrive to use as a backup disk, but don't leave it connected to your PC all the time) It's a good idea, especially if your hard drive contains irreplaceable or valuable data. At least copy your files to a USB Flash drive and use a free file-syncing service like Microsoft Onedrive to create another copy of your personal data.

11: Always download programs and files from reputable sources only. Filehippo, and others like it scan all their files and programs for viruses and malware before offering them for download. See my Freeware page to find good free software.

12: Watch the installer when installing new software - especially freeware. At times these installers will attempt to install software you neither want nor expect. Decline all extra software installs.

13: Keep your software updated.
    Especially internet programs such as Adobe Flash player & Reader, Internet Browser Software, and Oracle Java. Updates for these programs are normally offered for the express purpose of closing security holes. Don't ignore the update prompts for this type of software.

A note concerning Adobe Reader and Java.
    Internet helper programs such as Adobe Reader and Oracle Java are not essential.
    Foxit Reader & SumatraPDF are good, safe, and fast alternatives for Adobe Reader.
    Oracle Java is not necessary for general internet surfing. Very few sites require Java to be installed on your PC and very few programs need Java to function. These sites and software programs have many good alternatives.
    So if you wish to uninstall Java to avoid its problems, feel free to do so.

    If you want to speed up your PC disable unnecessary startup programs and/or install more Random Access Memory (RAM). (RAM is not that expensive now.) See Is your PC running Sloowly Now? for help.
    If you really want to energize your PC install a Solid State Drive (SSD). They are a bit on the pricy side, but well worth your money if speed is your goal.

Other things you should avoid.
1: Do not send attachments in emails unless they are requested.

2: Do not use stationary or any other kind of special formatting in emails.

3: Do not TYPE IN ALL CAPS.
    This is considered shouting, especially in web forums.

4: Avoid texting speak in forums.

5: Do not poke sleeping bears.
    Most REAL hackers are quite content to leave you alone unless you make them take notice of you. No dinky little software firewall or consumer grade router is going to keep them out of your system. So do not go to some hacker website or chat room and start shooting your mouth off unless you're prepared to accept the consequences.

6: Avoid using online registry or PC check sites.
    Most of these sites and programs are scams, and wish to sell you something you don't need. Most of them report non-issues in an attempt to boost the number of "issues".
    Sometimes using these programs can lead to a non-functioning computer. There are some reputable sites such as online malware scans from some of the top antivirus vendors, but before using any other check it out!

7: Another last warning about Windows Registry.
    The Windows registry is not some mystical black box of untapped performance tweaks for Windows that will lead to untold improvements in system performance.
    Most of the tweaks will lead to very modest performance gains of 1-2% tops, and probably less than 10% all combined. There is also a good chance that you will render your system unbootable if you make a mistake when editing.
    Registry default settings are set that way for a reason. Just do yourself a favor, and forget you ever heard of the Windows registry until you have gained sufficient knowledge of the dangers of Registry editing.
BE VERY CAREFUL! Data loss and re-installing Windows is NOT fun.

If you should get a computer virus or malware on your computer use another PC to access internet help forums - such as Bleeping Computer - for advice on how to get rid of it. Quite frequently the advice you will receive will require that you have more than a passing knowledge about computers. So if you would rather have a technician solve your problem for you, be sure of the charges before leaving your PC with him/her.

Disabling Startup Programs
Unnecessary startup programs slow the startup of all PCs and since these programs are always running in the background they use valuable RAM memory that may be in short supply, especially on many older PCs with little RAM installed.

It is possible for a user to run the Task Manager startup tab (right-click on the taskbar then choose Task Manager from the context menu) to disable some of these unnecessary or unwanted startup programs. However the best way to rid yourself of troublesome startup items is to change the settings of these programs or as a last option, uninstall the programs that put them there in the first place.

If you prefer to use a third-party utility then download a program called Ccleaner from Filehippo.com. Ccleaner is for beginning to moderate users. The Ccleaner program also does a very acceptable job of cleaning the trash files from your PC.

AutoRuns for Windows is also recommended. (download it from Microsoft Technet). Autoruns is for advanced users. Be careful with this program!

To learn how to safely disable unneeded startup programs see my page Is your PC running Sloowly Now.

Last things
In Windows 8 and 10, the revamped Task Manager now includes Tabs, including one called Startup which includes the feature to control and disable startup items, very handy! MSConfig is no longer necessary for this and it's startup tab redirects the user with a link to the Task Manager. Right-click the task bar then choose Task Manager, then click More Details to see all the Tabs.

The benefits of being paranoid