BSOD: Driver_IRQL_Not_Less_Or_Equal

This BSOD (my first with Vista Ultimate since it's initial release)

STOP: 0x000000d1 (0x0000002c,0x00000002,0x00000000,0x804063c4)

nvstor.sys - address 804063c4 base at 80402000, datestamp 458d543d

nvstor.sys driver

Specs:
ASUS M2N-E
AMD X2-5200+
2x1GB CORSAIR XMS2 (PC2 6400C4)
ASUS EAX1950PRO/256M Radeon X1950PRO PCI-E x16 Video Card
WD Raptor HDD-(Sata)

* There has been no recent HW/SW changes
* No new drivers installed
* Same configuration as initial setup of Vista Ultimate
* No Overclock
* All SW/HW Vista Compliant

Might not be related but just prior to the BSOD I had been playing Vista
Game Mahjong Titans

When this first occuured I thought it was related to Video Card so I
installed the latest ATI Driver.

However, some research leads me to think that "nvstor.sys driver" is the
storage driver for nVidia based motherboards. Is this correct???

Things I've done since receiving the BSOD:

1. Installed new Platform chipset drivers from Nvidia driver site for my
mobo(M2N-E)

2. Installed updated ATI driver for Radeon X1950PRO Video Card

--
megatonone