Recently, my PC's been giving me things at random saying "An unauthorized change has been made to Windows", and it always happened if I logged in too fast, or if I tried to run the WGA Diagnostics tool, which would first pop up "Genuine", but then show "Invalid License" until I restarted.
Not a big deal because I know for a fact that my copy of Windows is legal and it didn't bug me that it thought it wasn't genuine, but it wouldn't let me access the control panel. So, I tracked down what was causing it, and it lead straight to Avast. I uninstalled it, and sure enough, problem solved. It was good using you Avast, too back you suck now.
Anyway, I need a new antivirus, as I'm currently without one. It has to be free, don't suggest Norton or McAfee or I will laugh at your stupidity, and it has to work well. Give me suggestions.