I just cannot get them to install properly...

I've disabled driver signing - tried both Windows 7 and Windows Vista x64 versions and neither are working...

What did you guys have to do?

For what kind of hardware (exact type) are you trying to install nvidia drivers? If they don't work in any Windows >= 6.0, I think you have the wrong drivers.

Running a dual quad core xeon with a 8800 Ultra

What OS are you running? Vista? Windows7(what build)? Or are you running Windows server 2008?

If your running server 2008 you should be able to install the Vista driver and have no problems. If your running x64 OS you must make sure your trying to install the x64 driver other wise it will fail.

The following drivers corresponding to your OS should work:
Windows 7 x86: http://www.nvidia.com/object/win7_x86_181.71_beta.html
Windows 7 x64: http://www.nvidia.com/object/win7_x64_181.71_beta.html
Windows Vista/Server 2008 x86: http://www.nvidia.com/object/winvista_x ... _whql.html
Windows Vista/Server 2008 x64: http://www.nvidia.com/object/winvista_x ... _whql.html

If you can't install them normally, try to unpack them using 7-Zip and install them manually. More info in the Manual at the Drivers page - Method 2.

Good luck!

Arris

Another option is to download drivers from the Microsoft Update Catalog:
http://catalog.update.microsoft.com/v7/site

In my case, the packages from nVidia would only install the HD Audio driver for the HDMI output, but not for my graphics card (9300M), but the latest driver from the Update Catalog worked fine. So if you're having trouble with getting drivers to install, it's worth a shot to check there.

Note: the Catalog has a ton of different drivers, so be sure to check you get the one for x64 before you download. Click on the driver name for an info popup.