Here we go. A friend of mine started having some interesting problems arise on his PC. I took it home and reformatted the HD, reinstalled drivers and progs and everything was running fine for a couple of days at my place. I took it back to his house and set everything up for him. Just a few min after connecting the webcam, printer, ethernet cable, and speakers the computer started running very slow. Opening up the task manager I saw that one of the svchost processes was using up 99% of system resources.
I know this could be a trojan or a worm, but how does it just show itself when I connect at his place? Could it hide itself in the router? Would a hijackthis log help?
EDIT: Thread title renamed