Vista - PC not shutting down or restarting properly

About a month ago, I started having problems with Vista Home Premium not
shutting down or restarting properly. The system exits Windows and goes to a
black screen like normal and cuts power to all the USB devices. However, on
shutdown, it is still idling, the PC doesn't turn itself off and it's sending
signal to the monitor so the monitor doesn't go into standby mode. On
restart, it does the same thing but doesn't reboot. I have to manually shut
it off by pressing and holding the power button. If I don't do that, the
system will sometimes reboot itself after a long period of time (10+ minutes).

I think this problem started about the same time I updated the driver on my
EVGA Nvidia 8800GTX. I remember getting a couple error messages after it
rebooted itself about a catastrophic graphics driver failure come to think of
it. I've since updated the driver again but the problem still persists.

My system:

Vista HPE
Asus Striker Extreme mobo (running onboard sound)
EVGA Nvidia 8800GTX vid card
4GB Corsair XMS ram
2x250 Toshiba HDs running in RAID 0

I'm having this same problem mate. I noticed there's no replies yet but i'm 90% sure it's graphics card driver related.

I've got 8800GTX and when i updated to decent drivers it won't shut down

My dad has 8600GTS and when i updated to decent drivers it won't shut down

SO, it's probably "8 series" driver related. Hurry up nvidia you slackers!