I am having similar problems. Since I installed Windows 7 yesterday I haven't been able to work on it for more than 15 minutes. It just freezes. I ran Windows Update and it said I had some driver updates for my monitor (Syncmaster 940BW) and an update for my video driver (Nvidia 7900GT). I installed them but after a reboot, the freezing got worse.
Now I could only use the pc for less than 2 minutes and it freezes. So I rolled back the driver for my Nvidia card and the problem was reduced again to 15 minutes after reboot freezing.
If I reboot in safe mode, then I have no freezing problems. So I'm guessing my videocard is creating the problems. I disabled hardware acceleration, but that didn't help.
I also tried an older Vista driver for the 7900GT (182,50 instead of the 185,85 designed for W7) but no improvements there.
The only things I was running were firefox, Msn messenger and sometimes an installation program (I installed Java DK and Shockwave, that's it), nothing intensive.
My setup is as follows: Core2Duo E6600, 2GB RAM, 100GB WD NTFS partition (this is where Windows 7 is installed), Nvidia 7900GT and the motherboard is an Abit AB6.
I updated the drivers for my Realtek LAN and Realtek high definition audio device and for my motherboard. But this didn't do any changes. It's just when I modify the video driver that something happens (With the newest driver my pc freezes after 2 minutes, with an older driver it freezes after 15 minutes)
The installation was a clean install and I have no other OS installed. My last OS on this machine was XP but I did run Vista on it for a couple of months without any problems.
I'd really appreciate your help because I haven't got a clue what else I can do and I really don't want to downgrade again to XP/Vista.
Edit: Forgot to mention I'm running the 7100 32bit build.
Edit2: I'm pretty sure it's the 7900GT that's causing the freezing.
I went to device manager and display adapters. I right-clicked on Nvidia 7900GT/GTO and selected uninstall. When prompted if I was sure I also confirmed the option to delete the drivers.
After a reboot (not in safe mode), Windows told me that the driver (7900GT/GTO prerelease - WDDM 1,0) was succesfully installed and I needed a reboot to let the changes take effect. I didn't reboot and I haven't had a crash since 40 minutes ago.
Everything is running fine, except for the Nvidia driver which still needs a reboot.
I looked it up and some people suggest to install a older driver in compatibility mode. Does that mean to right-click on the installation file (for example, a driver designed for Vista), Properties > Compatibility > Run this program in compatibility mode for > Windows Vista? Won't this just run the installation program in Vista-mode, but still run the driver itself in W7-mode?
Edit 3: After 3 hours my pc froze, without the Nvidia driver working. So I don't know what's causing it.
Anyone have any ideas what could be causing this?