Updated nforce drivers now has random crashes

A bit about my PC.
I use this as my internet surfing/TV media center/gaming machine
Specs:

Windows Vista Home Premium 32bit
Case: Antec Nine Hundred
Power: Antec 750 Watt Modular Powersupply
MotherBoard: Abit Fatal1ty FP-IN9 SLI (650i SLI chipset)
CPU: Intel Core 2 Duo E7200 2.53Ghz OverClocked @ 3.08Ghz
RAM: 4 GB Dual Channel PC2-6400
Videocard: Visiontek Radeon HD 4870 512MB
Soundcard: Asus Xonar D2X 7.1
Harddrive1:Seagate SATA 300GB (Vista OS)
Harddrive2:Western Digital SATA 500GB (Games)
Harddrive3:Western Digital SATA 1TB (Media Center Storage)
DVD-RW1: IDE Memorex
DVD-RW2: IDE Liteon
TV Tuner1:HDHomerun Dual ClearQAM/ATSC Tuners
TV Tuner2:Hauppauge HVR-1600
Wireless Network: Linksys Wireless-N dualband PCI adpater
USB Xbox 360 Wireless Reciever
USB Logitech G15 Keyboard
USB Microsoft Intellimouse Optical
USB Media Center Remote Reciever w/ Remote

Ok, now this morning I stayed home from work and I had noticed there was an update for Nforce drivers released yesterday I believe updated them to 15.51. I downloaded the new drivers and installed them ontop of my old drivers. It asked me to uninstall the old ethernet drivers first so I said yes.(My ethernet port is connected to the HDHomerun, my Internet is through wireless) It rebooted and I tried out my TV tuners in Vista Media Center and everything seemed to be working fine.

So I decided to watch one of my recorded TV programs and about 5-10 minutes into the show, the video started to glitch and the monitor lost video signal and went to standby mode, at the same time, the sound glitched then it just repeatedly looped the last audio sample played. Also the videocard fan revved up to full speed, which sounds like hair dryer. I got all freaked out and held in the power button on the case until it turned off.

I push the button again and now my PC comes back on. It boots up normally aside from the boot menu which wonder why it wasn't shut down properly. I do the normal boot and everything works fine. This happened before noon. Now I used the PC all day, I played Batman Arkham Asylum quite a bit, then I watched some more TV shows in Media center, it showed no other problems. Tonight, maybe about 2 hours ago, I was playing some Left 4 Dead on Steam and maybe 45 minutes into the game I get a system crash which is EXACTLY like how it crashed this morning. I think about those new motherboard drivers from Nvidia and say well those have got to go!

I tried to uninstall them from the control panel while I download the older version 15.25 I think(for nforce 650i SLI). Upon uninstalling the 15.51 it asks me to reboot, which I do then windows installs some drivers automatically. then I run the older driver installation of the 15.25 version It asks me to overwrite a file when I run the setup. which it didn't do before. Then after its done, I have to reboot again.

Now while I wait, I leave the room and I hear it boot up from out of the room and just ask I walk in the door to check on it, the Graphics card is revving up to 100% fan speed and the monitor is going into standby mode, it means the damn computer is crashing on the desktop without any programs even running.

After that, I am able to reboot again and I run system restore, I find the most recent restore point which is from last night, about 12 hours before I installed the new drivers this morning. I run the restore point and it restarts the computer. I breathe a sigh of relief and get back on steam to continue my game of Left 4 Dead with my friends.

less than 30 minutes into the game it crashes again the same way as the last 3 times. 4 crashes in one day. Thats when I start searching google, I can't find anything on google, then I came here desperately looking for help. The machine needs to be stable since it is being used as a DVR, it stays on 24/7

It seems to be getting worse. I uninstalled the PCI management driver from from the nforce package and disabled the sound card. I was in the middle of a DVR recording when it went out this time.

My GPU has the fan at 40% and it stays around 50C
CPU has an aftermarket heatpipe sink and 3 intake fans and 2 out fans on the case. It was overclocked to 3.1Ghz for almost 6 months with no configuration changes. Now after my first few crashes, I reset the CPU to stock speed and I am still getting the random crashes.

At this point I am willing to reinstall windows to see if it is a software or hardware problem.

yes stay away from nvidia chipsets