BSOD- Stop 0x8e (0xC0000005...)

Before I describe problem, understand I work on computers daily, in a shop, and I can usually solve this. But... my brain does not feel like working today, and I can't remember how I fixed this before. Anyways-

When trying to play a DVD file, the customer receives a BSOD with the following stop codes:
0x0000008E (0xC0000005, 0xBF260710, 0xB5556B30, 0x00000000)
etc etc
nv4_disp.dll etc etc
Now I realize that Only the stop code and first parameter are the helpful ones, but I put them all in just in case.
I've already tried updating the nVidia drivers, checked the RAM (tested and swapped), and installed a new codec pack (although I didn't actually think it would work...). Anyways, I'm stumped, and it's pi**ing me off. The customer CAN however play his Battlefield games with no problem. Anyways, let me know if you have actually fixed this before, I've read plenty of forums where people say ''well Microshaft says this'' etc... no offense, just read way to many forums like that. I need an actual solution that someone has used and works.

Oh- System specs (duh)
Dell Dimension E510
XP MCE SP3
Pentium D 2.80 GHz dual core
3 Gb DDR2 (upgraded)
Geforce 9800 GT w/ aux power (upgraded)
Capable power supply