Tried running up-to-date avti-virus and up-to-date spyware/malware detection programmes? From what you've said it certainly sounds like one of those, and by the way, get on to the makers of the computer, they should be able to supply you with all the disks (even if they are only OEM copies) for EVERYTHING they pr-loaded - including Windows! It doesn't matter that it's out of warranty, I bouoght a computer that way a while ago, and I was only sent copies of the OEM XP disk, I phoned up and got the disks for the various pre-installed programmes by return of post.
The trouble is that a lot of the pre-installed programmes are not really suited to our needs, you'll see what I mean if you look at my profile, the only thing that was in that computer I bought, and the one I have now is the case!
A guy in the office was transferring images from his digital camera to his PC when the screen froze. He now can't start up his OS unless in safe mode. I've tried "last known good configuration", used an old restore point, checked for clashes in Device Manager, done a diagnostic startup using msconfig and still no joy. The machine is out of warranty and we can't find the recovery disks anywhere. Also, because the software was preinstalled there's no original disc to do an XP repair job on it. What more can I try?