Vista - Assorted problems with quad core,848MB Geforce GTX260, and Vista

Hello, I have been using Vista Ultimate x64 almost for a month now. Currently I am seriously thinking about going back to XP. My system specs are: Intel Quad Core (Kentsfield), 5 GB Ram (2 sticks of 2GB G-Skill, and 1GB of Corsair), EVGA GeForce GTX 260 Superclocked Edition 848MB, Arctic Cooling Freezer 7 Pro 92mm CPU Cooler, EVGA 750i SLI Motherboard, 800GB Western Digital Sata HD.

I installed GTA 4, and it crashes before it even loads the game.
Installed Saints Row 2, the intro movies work, then it crashes before it gets to the main menu.
I installed GRID, now for GRID, the Drift GP style races crash the game. Also, after I complete the first race for the campaign, the game freezes and crashes.
Fallout 3, works great under Ultra High Quality, went outside of a city the last time I played and the only thing I could see was my character and the ground, nothing else.

I have run across multiple problems with Vista Ultimate x64 on my quad core... yeh Vista is nice and all, but I am one step away from going back to good ole XP and just DL'n some addons for it to make it looks like Vista. Im going to install Vista x32, not Ultimate, and see how my system handles it first before I fully go back to XP.
I also would rather not go back to XP because of DirectX10, but... I really don't notice THAT much of a difference to have to suffer not being able to play other games because im using Vista.

I just got done doing a bit of looking around on these forums, and DL'd the Directx9/10 patch, as well as verifying that I have the latest drivers for my motherboard and GFX card. I have tested different screen resolutions and many many different combinations of things to get these damn games to work but to no avail. Any advice? Thanks!

Are you sure your RAM is compatible? Are they the same mhz? Have you tried or tested the rig with only the 4GB of G-Skill ram? What driver version are you using for the GTX260? I know you said the latest but, indulge me if you don't mind.

Took out my extra stick of RAM, everything is still the same, no noticeable changes.

The driver for the GTX 260 is - Version 7.15.11.8120

Hmmm, I just got finished restarting my PC because I updated that driver to this supposedly newest one. In device manager, its showing the version 7 driver, not sure why its not updating to the right version... sigh.

There have been problems with the 750i board. 750i Help

That could be an issue.

~Lordbob

P.S. 300TH POST! YAY