Dowding, do you have all the 'critical files' updates from Microsoft? I used to have simliar probs back before the con, then Skuzzy, the nice guy he is, updated my machine with all the critical file patches that WIN98 had released....dunno if this will fix YOUR particular problem, but you should certainly start with updating every driver and your OS system first...
Another after thought,do you have WIndows managing your memory, or do you manage it yourself, and if yourself, what MIN/MAX do you use?