I replaced the chip with another 64M RAM chip to get 128M on the system now. Seems to run better, but I won't know until a week or so after he has used it a lot.

I suspect it could have been a bad DIMM, I used a DIMM from the old system, but replaced it today with a known good DIMM. Or maybe the old DIMM (PC100) was not compatible with the new motherboard?

98, XP, 98, W2K, in that order. I hope this doesn't confuse my father about which OS he will use.