Troubleshooting an XP BSOD

This one is a bit of a puzzle.  I've been playing an online game for a month 
or two and once in awhile I'll get a BSOD.  Checking the game's online 
forums seem to indicate that it's a sound issue.  I've tried several 
different versions of my sound card drivers, and reducing my hardware 
acceleration.  So far I haven't had any more BSODs while I was playing the 
game...but the strangest thing happened.  I woke up this morning and noticed 
that my computer had rebooted overnight.  I checked the system log and sure 
enough:

0x00000019 (0x00000020, 0x86477000, 0x86477928, 0x0b250000)

Now seeing as how the computer wasn't doing squat at 2AM, and I was in bed, 
I don't see what could have happened.  Every online resource points to a 
device driver...yeah that narrows it down a bit.  :-/