Now that I have reformatted my desktop into Windows 7 (using XP before for 2 weeks) I am using Microsoft's free AV "Microsoft Security Essentials". I couldn't download it before in XP because it requires me to download the Genuine Notification Tool which will make my screen black and harass me with pop ups to buy a legit CD-key! Apparently they think my Windows 7 is legit so I was able to download it hassle free...