The other day I noticed that my friend's computer (Windows XP) was running very slow, so I downloaded Avast! for him and ran a pre-boot scan. I found several trojans and ordered them all to be moved to chest; though none of the files that I moved to the chest were infected system files.
After I finished the scan, the pc started to boot up but instead stopped at a black screen. I restarted the machine several times after this but only ever got the same black screen. I am able to get to the bios but am unsure of what to do at this point.. once I back out of the bios I just get the black screen again.
help!