I know the info I have for you is a little vague, but here goes:
The customer has complained several times about his Windows 98SE machine Bluescreening while online. Before he can read the error or hit a key, the computer opens the AMIBIOS CMOS Setup screen. He swears that he didn't hit DEL or anything else to cause it. We've wiped his HD and reinstalled Windows. Before we did that he kept getting shell32 errors. I'm afraid I don't have the info on everything we did this last time, or what his system components are, because my boss did the work and didn't charge the guy anything. I know, it doesn't make sense. But anyway, the guy is complaining about it again. The only thing I can think of is a bad motherboard.

Any other suggestions?