<I'm running XP Pro SP2, AMD Athalon XP2000+, 768mb RAM, NVidia GeForce FX5200 256mb RAM.>
This setup is identical to mine, before the failure, except mine has 512mb main board RAM.
Mine suffered random lock-ups and crashes, it usually failed as soon as a multimedia file was clicked on. Got many different blue screen failures quoting drivers and memory addresses. Sometimes it would complete a full boot, sometimes not. At least CPUs are cheap just now and a lot easier to fit than a new motherboard.