Oblivion crashes in Vista

[scifier]

Help. Just got Oblivion to play on the new Gateway I got to replace the HP that just died. Loaded up Oblivion, Knight of the Nine, Shivering Isles, and a bunch of mods from the Fivefries Oblivion Modlist. Loaded all the mods according to the load list on Fivefries. System stats below:

AMD Pehnom 9500 Quad Core Processor 2.20 Ghz.
Vista Home Premium 32 bit Service Pack 1.
3 GB Ram
Radeon X1600/X1650 Series 512 MB, driver 8.493.0.0 dated 5/12/2008.
Realtech high definition audio driver 6.0.1.5506.
Optiarc DVD RW AD-7203 ATA Device
500 GB primary drive, 340 GB secondary drive and 250 GB tertiary external drive.
Base score 4.7 on the windows rating system with graphics as the base score of 4.7 and gaming graphics as 4.9. Processor was 5.8 on a 5.9 max. Oh yeah, and running Direct X 10.

The Oblivion Tech system said that I was running Windows Workstation 2000 Version 5.1, Service Pack 2, Build 2600. Don't know where Oblivion is getting that information. I'm running Oblivion under administrator and Windows XP Capatability.

Started up the game and everything goes very well, skipping the tutorial after clicking on the lantern. Sometimes I get the guy from the Cybiades mod before exiting to outside, sometimes not. Get outside, birds singing, wind sighing, everything looks wonderful. Run toward the city and as it get ready to change cells it crashes. Tried over and over and no matter what direction I go when the cell changes the games crashes. After the first crash I got a Windows message that my graphics driver was not compatible and to upgrade. I already have the most recent driver but I installed it again just in case and it still crashed.

Questions: Would this work with direct X 9 or an older video driver? Would it work with Windows XP? I'm thinking of reverse upgrading to Windows XP because some other programs I have that were working are now not working. Would it work to dual boot with Vista or just wipe Vista from the system? Any suggestions would be welcome.

[Prew]

My son played Oblivion with many mods, including new soundtracks, and the expansions on Windows XP and a Radeon 1800. He did not have any problems at all with it- he thought it was a really good game.

I've tried Vista a few times but always went back to XP because of crashes.