As well as displaying unusual and slow activity, Gmer reports rootkit activity even after a fresh reinstall. After flashing the bios and restarting, the computer displays only a black screen for approx 5 minutes when turned on, then boots as normal. This only happens directly after a bios flash, and it seems suspicious. At this point I am beginning to doubt the results and am suspicious of a hardware issue, but gmer has never failed me before, and the computer was definitely infected when I started working on it. Malwarebytes removed 3 trojans, but the infection persisted when I first received it, so I wiped the hard drive. On reinstall, Gmer reported suspected rootkit activity, so I booted up on a linux cd and wiped the mbr and the whole drive, then reinstalled, with the same results in gmer. I then flashed the mouse, bios, and cd drive firmware, wiped the mbr and the drive, and reinstalled again. The PC bluescreened when i ran gmer again, and displayed warnings about hard disk integrity. I shut off the computer, then entered dell's diagnostic tool from the f12 boot menu, but the built in hard drive diagnostic tool never advanced past 0%, despite running it 3 times for an hour each.
PC is a dell studio hybrid 140g running windows vista. I have formatted the hard drive and wiped the mbr 8 times now, trying different things. An issue is that the bios updates can only be run in a windows environment, so I can't be certain they are actually working, since I am running it in a possibly infected environment. It's my mothers computer, and I'd really appreciate assistance in figuring out what to do next. I am completely lost at this point.