Antivirus that is a virus.

Any anti-virus we use the same, the important you should update your anti-virus periodically. Because when your pc/notebook get the lastest virus and your anti-virus has not update so the anti-virus will not detect the virus. When they are exposed to the virus damages the file system (win**ws) you should repair or reinstall your OS. before it did backup your data first to an external hard drive / another local disk (like d:, if the system OS in c:) using linux (bootable cd like ubuntu or puppy). :)

I have been using Avast Anti-virus software and I must say that it is the best free anti-virus out there. I don't think it's the reason why you have virus in your computer. I know some Anti-virus software that will really make your computer miserable so you can upgrade your accounts with them, but Avast is not one of those. Maybe you can system restore your computer or you can also download Malware Bytes so you will know the problem.

Avast is the best one to use. You probably just had a corrupt system file. Simply re-install it and it should be fine. But if you really want to use something else, Eset NOD 32 is good, and I've also heard that Kapersky is good as well. But most people I know recommend Avast, it is the most reliable one.

Just wanted to let you know that antivirus software will not prevent you from getting all viruses. They catch most of them ,however once and a while one gets by them and you have troubles. This is especially true for the free antivirus software. Sounds like a virus just got by your software. The expensive paid for antivirus software is better, however newly created viruses can even get by those as well. It's a Jungle out there at times.