Preventing your computer from becoming infected is infinitely easier and less stressful than cleaning up after an infection.
Search my site for tons of information on setting up your computer for security and techniques to avoid scams. However, if you are already bit by one of the most recent nasty forms of software, Antivirus 2008, Antivirus 2009, Personal Antivirus, Internet Security 2009 among others (software I call extortionware that installs itself on your computer and then poses as legitimate software you have to pay for to get rid of the problems. Problems they caused), follow the steps at this site to get back up and running and then come back here and learn how to prevent it from happening again.
Earlier this week, I wrote about how some of these things get onto your computer and it is a must read for any computer user.
Two other links that will be helpful in cleaning this and related malware off of your computer are ComboFix and Malwarebytes.org. Some of the first actions these rogue software products accomplish when on your computer is disabling your antivirus, windows updates, and system restore. They also prevent you from visiting legitimate web sites like I have linked in this article to make it harder for you to remove the pests.
You are probably best served visiting my site on a non-infected computer, download the two products, change the original file names (this is important because the rogue software will also disable known products from running at all), copy the two tools to a flash drive and then take them to the sick computer and run them per instructions in the article I linked in the second paragraph. I suggest running the ComboFix first and then run full scans with your antivirus software and malwarebytes.org’s product as well.
I’m linking to BleepingComputer.com’s article because they do a good job of giving you a safe download site and thorough instructions on how to delete Antivirus 2009 or 2008. Even if you aren’t infected, it’s worth visiting the site to see what kind of work is required if you do get infected. It might also motivate you to read my site more often and follow the advice I give to keep you safe and productive with your computer.