How to identify and remove a virus or malware

You may have arrived on this page for a couple of reasons a) because you think you have a virus and want to be sure b) you know you have a virus and want to remove it. Either way it is best to be sure that you are in fact dealing with a virus or malware.
SYMPTOMS OF A VIRUS

• Slow startup
• System crashes and reboots
• Printing failures
• Freezing
• Unexplained high processor and memory usage
• Errors
• Internet explorer homepage has changed or is taking you to the same website when you click different links
• Last but not least – your anti-virus or anti-malware program tells you, you have a virus !!

So lets assume your PC is doing one or more of the above, what are the next steps ?.
Anti-virus : If you haven’t already got this installed, get it as soon as possible. Once installed, get the latest updates and then run a full system scan. The software should identify the virus and remove it for you or provide you with information for manual removal. See software recommendations at the end of this post.
Anti-Malware : Anti-virus doesn’t always pick up Malware so it would be worth while downloading a separate program, installing, getting the updates and running a full scan. Once again, the program should remove it for you. See recommendations at the end of this post.
THE THREE OUTCOMES
Software removed the virus : Excellent. The software did it’s job and is money well spent. If you are using a free program – even better !!
Software found the virus but couldn’t remove it : The software should provide you with information on the virus and give you the steps you need to follow to remove it manually. Once you have completed these steps re-scan your pc.
Software has removed the virus, you’ve rebooted your pc and it comes back !! : Don’t worry this is actually quite common. Many computer viruses are designed to self replicate and spread themselves through-out your system. For example a virus may contain 100 files that it distributes among the directories and settings of your pc. Your anti-virus may find the main 80 files and does a perfect job of removing them, however, when the PC reboots the virus is able to rebuild itself using the 20 remaining files. The solution is to research the virus and find some manual steps or a tool to remove all of the files. Once you have done this make sure you re-scan the PC to verify it’s removal.
Hope you found this useful. Please leave a comment :-)
RECOMMENDATIONS
Anti-virus
AVG Free Edition
Avira Personal Free
Norton Anti-Virus
Anti-Malware
Malwarebytes Free edition