Fozz,
I've had similar problems especially due to Detonator reference drivers 3.78 and lower, seems to be after I'ved accessed an OpenGl app, ( always happens with OpenGl based screensavers ). If your card is an ASUS, try the new Beta1 3.79 it fixes the allocation bug with AGP.
Adaptec 4.01 causes faux BSOD with any cd dupe.
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PIII 450
128 MB RAM
Asus P299 Mb
Asus V3800M64 TNT2
Memorex CR-622 CDR