I wouldn't have believed it. I'm writing this in case someone else has this problem, even with another type of drive.
The DVD Burner I've used for years was causing a BSOD in XP x64!
I've been using XP 32 bit for over a year now, dragged kicking and screaming from upgrading my trusty old Windows 2000 machine. I made a cheap upgrade from an old dual AMD MP (MSI K7D) I had used since about 2002, to an AMD X2 overclocked to 3Ghz. The motherboard has only 1 IDE port (but 4 sata ports), so the old BenQ 1620 plugged in there.
I have two sata drives as 'main' boot and storage, but my trusty old WD 320G drive (a pata) is a good 'auxiliary' storage when speed isn't critical.
The BenQ never liked being a slave when it shared the cable. The IDE didn't even recognize the drive existed unless the BenQ played master, so the WD took the slave position. This was fine under XP 32 bits.
A recent graphic project on a 148 inch wide 'poster' (backdrop for a display booth for some show a client was attending) caused me to rethink 32 bits. So, I swapped the sata drives, installed XP x64 on the 'new' drive 0, and started installing anti-virus, firewall, etc.
Then, random 'STOP 0x00000050' in disk.sys (BSOD) - PAGE_FAULT_IN_NON_PAGED_AREA. Sometimes it would happen upon bootup, sometimes after 30 minutes. The machine ran all night with a VM downloading stuff, but after launching a couple of applications in the morning, BSOD.
This makes debugging the problem really tough. Failure is deterministic, but an hour or two of flawless runtime means nothing. I swapped RAM chips (RMA'd two sticks even), removed RAM chips, network cards, re-installed the OS, updated drivers - all the obvious things to try.
Never once in 3 days did I consider the DVD drive.
Searching the 'net found very little to help (which is why I'm writing this - CDFreaks sometimes comes up in various search engines when trying to find these kinds of problems - maybe this will help someone else).
Once I removed the BenQ - the problem has not recurred in over a week.
The strange thing is, I could really stress the machine without a problem. With the BenQ in that odd position, I could run 5 VM's with various operating systems, browse the Internet, update Linux, play music - no problem for about an hour.
Randomly, the BSOD would haunt me. I nearly gave up.
The BenQ was the problem. Once I pulled it off the IDE cable, the OS has been stable ever since.
I had a SiliconImage 0680 IDE card in a drawer, which I installed, to give me two IDE ports. My nForce430 board won't let the built in IDE operate when the Sil 0680 is installed, but that's minor. With the BenQ on a channel by itself, and the old WD 320G on the other, the machine is as stable as a rock.
I can't boot from a DVD this way, though. The Sil 0680 driver isn't on the stock XP x64 disk, so it refuses to boot. I may have to create a slipstream copy in order to get that on there, otherwise I'd have to pull the Sil 0680, plug the BenQ into the onboard IDE (without the WD 320) - which is how I installed XP x64 for the last time.
I should either retire the WD pata drive, so I can put the BenQ on the onboard IDE, or consider a sata DVD drive, but all that can wait.
At least I've got the OS stable again.
I have some cause to think Vista x64 might not have crashed the same way, but I wouldn't put that on my machine if it were free.