This is a problem that has existed in Vista from the very beginning, as I found out the hard way after its release in December 2006. If you use any Nvidia Forceware drivers other than version 158.24 you will get screen corruption like in the picture below when changing resolutions.
This situation only applies to factory overclocked 7900GT cards and the solution is to either under/overclock the card slightly.
I’m posting about this today because I had forgot about it until recently when I was reinstalling my brother’s computer, upgrading him from XP to Vista after a nice virus he got on MSN. I preferred to modify the card’s BIOS directly instead of just changing the clocks in software with Rivatuner.
The change is very straightforward, just change the 2D & 3D clock speeds on the main page and then save the file in .rom format as modded.rom. Obviously make sure that the card is 100% stable at the new speeds and corruption free. For flashing use nvFlash, make a clean MS-DOS boot floppy and copy the nvFlash util and BIOS to it, to flash just boot from it and type “nvflash modded.rom”