I am facing this problem since about 2 months. Whenever i try to install any antivirus on my Win XP OS, either it refuses to install (Avast) or if it installs , it refuses to run (Kaspersky). I think this is related to some virus existing on my HDD. I have formatted my OS partition 3 to 4 times in these two months and reistalled the OS (due to some or the other problems caused by this virus/es. For eg, some softwares like KLite , Folder Lock etc can be initiated only within couple of minutes after the windows start. Make any more delay and i have to install the softwares again to run them and that too if i run them immediately after i install or else reinstall again) I believe that it is the problem of some virus on my non-OS drive because i used my friend's Win XP cd to make sure there is no problem with my cd. Also i cant format my HDD completely because there are quite a GB's of important data scattered on my HDD.So, if you guys can suggest some way to scan my hdd with antivirus from bootable disc or something like that. Or if you guys think that the cause is something other than virus please guide in that direction as well.