I havent done a full scan in quite some time mainly because I havent done much of a variety on my computer. i would usually go just aim, play games, and surf the web. Yesterday I installed several games but they were all that my friend had so I doubt it could be the programs. I did however have a surge problem a while back that corrupted some files on my hard drive. My assumption was that if data was being written to those corrupted sectors, that it might be messing it up but I dont know enough about hardware, let alone hard drive errors to know for sure.