That title may be a slight exaggeration. This will not tell how to fix absolutely everything, but, it's remarkable how many problems can be fixed in these simple steps. Do you think you have a virus? Is your computer filled with ads? Is an 'anti-virus' program you've never heard of constantly telling you to pay up? These things can (usually) be fixed with the following five steps:
1 - Boot Into Safe Mode with Networking
Safe Mode is a version of Windows where the number of programs running is restricted to the bare essentials. This means you can complete the following steps without the malicious programs actively trying to stop you, which is a very good thing. One way to get into Safe Mode is to hit the F8 key while your computer is booting up, before the Windows Splash screen appears. This should open up a menu from which you can select 'Safe Mode with Networking'. While this works, it's not the easiest way. The easiest way to boot into safe mode is through System Configuration. Simply open up your start menu and search for System Configuration, or, you can find it in your Control Panel under System and Security -> Administrative Tools. Once open just go to the Boot tab, then check the 'Safe Mode' box and select the Network option from the radio buttons. Selecting the Network option is important. This allows you to use the internet while in Safe Mode, which you will need. System Configuration is the preferred method to get to Safe Mode because it will keep booting your computer into Safe Mode until you change the setting. This is nice because the following steps will probably involve restarting your computer multiple times, and this way you don't have to hit the F8 key every time.
2 - Change Your Proxy Settings
This step counters a dirty trick that a lot of these malicious programs play on you. These vile programs will go into your internet browser settings and change them to reroute all your internet requests through their 'proxy'. In a nutshell this means that no matter what address you put into Chrome/Firefox/InternetExplorer the malware will reroute you to their own nefarious site. To undo this just open Internet Explorer and click the Tools button, then click Internet Options. Now go to the Connections tab and click LAN Settings. In the LAN Settings window simply unclick the box that says 'Use a proxy server'. You will also want to reset your Home page. Note: You need to be in Safe Mode to do this. If you do it outside of Safe Mode the malware will simply revert it back to their settings.
3 - Download and Run MalwareBytes
Now it's time to do a virus scan. In my experience no antivirus scanner comes close to matching the power of MalwareBytes. It is not an active antivirus program, at least, not without paying for it, so MalwareBytes will not actively protect you from infections. But, when it comes to performing a scan and removing infections, I have yet to see it beat. You can download it here, or, you can use the wonderful website Ninite. Ninite is simply a tool to make installing a variety of programs as easy as possible. Once you have it, simply open it up and let it run. You will probably need to restart your computer after it has finished removing whatever it finds. Make sure when you restart you once again boot back into Safe Mode with Networking.
4 - Download and Run AdwCleaner
MalwareBytes should have removed all the really malicious stuff from your computer, all the viruses and trojans and things of that nature. But, there's a whole mess of things that can be less harmful than viruses while still being a royal pain. These are called PUP's, standing for Potential Unwanted Programs. Things like adware and those aggressively annoying toolbars are all PUPs. For the longest time there was no easy way to remove these devils. They were the bane of my existence. Then AdwCleaner appeared on the scene and everything changed. Life was good again. You can download it here. Important note: do not click anything on that page, the download should start simply by opening the link. Simply install it and run the scan.
5 - Preventative Care
Time to boot back into regular mode. Simply open up System Configuration once more, go to the Boot tab, uncheck the 'Safe Mode' box and then restart your computer. Your computer should now be blissfully free of all the crap you had to deal with before. If the problem hasn't gone away you have a deeper infection than these simple steps could fix and you will need a more specialized approach. But, hopefully, your computer is clean, and now that it is let's take some simple steps to keep it that way. The first thing is to have a good anti-virus program. If you have Windows 8 you're in luck, it comes with very good Windows Defender built in. Just get rid of any other, less good antivirus programs you have such as Norton or Avast or, god forbid, McAffee and then make sure Windows Defender is turned on. SImply search for the 'Action Center' and there should be a large, friendly button asking if you want to turn on Windows Defender. If you have Windows 7 or below I recommend Windows Security Essentials, which is basically the same thing as Defender. You can download it from Microsoft, or you can again use NInite. It's also a good idea to update your preferred internet browsers and Java to the latest versions, again I recommend Ninite for that. The final step is to run Microsoft Updates.