[E. Pluribus Unum]

I have used AVG and Avast. I like Avast a little better. I will try it. I am pretty sure you can’t do it. I got error messages when I tried.

[EasySt]

I can’t speak for Avast. AVG runs without complaint for me on a fully updated XP box, with Microsoft Security Essentials on it, as of last week.

[TheCipher]

I have used AVG and Avast. I like Avast a little better

I agree. However, I had a little problem ( as have others ) with the Avast 6.0 update. If you are running Vista, in some cases, it causes Windows to say that your license is invalid and you have to go to the Microsoft site to validate it, but the validation process doesn't work. You can still use Windows, but you get an annoying popup every 15 minutes saying your license is invalid. So I uninstalled Avast and went back to AVG and everything is back to normal.