I worked on a friends computer that has vista 64 bit and is an HP computer. I took on the chore because I thought his PC just had a disk error because it would reboot during start up. Once I got it to boot I realized his PC was infected. After scan I found between 400-500 viruses, trojans, adaware etc. His PC had zero protection and his firewall had been disabled by one of the infections.
After removal using every scanner I could down load to make sure all was gone. The system became unstable and eventually would no longer load. So I told the guy that format and reinstall to factory was his only option because it would never run right after all that was wrong with it from the infections.
Unknown to me is that he recently had his bios flashed. The flash deleted his build ID number which made his factory restore number not match the ID number. Which means restore to factory condition would not work (configuration error code purple).
After a while the restore would no longer boot and that was the end of that. I suspect that a virus got into the factory image. And I know HP will charge for this. So I told him that either i get one online download and tattoo it to make the numbers match. or buy window 7 and install from scratch. So are there any factory images to download or am I out of luck?