All it says on afg is that the shell, user and kernal have been modified... Thanks again.
Well if you've got Windows update turned on it's quite likely that an update has modified these items, and AVG has just spotted it when you rebooted, it's probably nothing sinister at all.
Do a full virus scan, to check for sure, then don't forget to mention to your Dad that if you were running Linux full time you wouldn't be worrying about this anyway
I have been touched by his noodly appendage.