windows 8 nvidia drivers

Since Win 8 is a pre-release beta version, there is no official support from Dell.  You are on your own if you install Win 8.  If it works great, but if it doesn't as in your case, you may have to reinstall the original operating system.  Installing the old OS may be a problem too, once you install something using a disc, the Dell recovery partition is no longer valid and you will have to reinstall with discs.  

If it had Windows 7, you can download and iso of the exact same version you had (e.g. Windows Home 64 bit), create an iso DVD (bootable) and use the Dell provided Windows 7 product key to reinstall.  Any missing drivers can be downloaded from the Dell downloads.

Win 7 download

The best option, too late for you, when you want to try something like this is to remove the original Dell hard drive, install a new hard drive and install on the new hard drive.  Then if there is problems, you haven't lost anything and all you have to do is swap the hard drive and you are back to where you started.

In cases where Windows doesn't have the correct driver and both Dell (and all OEM's) and device manufacturers (like nVidia) do not yet support Windows 8 in any capacity, you can use Windows 7 drivers instead.  Windows 7 drivers are as good as you are going to get right now, and they usually work just fine (both drivers from Dell and from the various device manufacturers).

If you are unable to get any drivers to work, then you'll just have to wait for the manufacturers to develop fixes/drivers to work with Win8.

"Most users hate the new Windows 8"

Windows 8 is a definite departure from the Start Button/Desktop arrangement we have been used to for the last 15 years, but having used it nearly every day for a week now, AND realizing that it is still in beta, I don't think it won't take users long to "get" what MS has done with the new UI, and if users give it a chance, they will grow to like it.  If Microsoft is convinced, as I am, that people will become accustomed to it, they will keep in and not give in to demands to change it, forcing people to learn the new interface.  Design is ultra touch-friendly, but it makes sense with a mouse too.

I tried windows 7 video drivers--they don't work. Neither the dell drivers or the manufacturers' drivers work. You have to let win 8 provide the drivers. Basically it does a great job with finding workable drivers.

There are very few drivers for windows 8 right now. You have to let win 8 supply the drivers even if they don't work well. If after you installed win 8 it booted before you tried to install the win 7 video drivers, that's the best video you can have right now. Printer drivers and other external hardware might install OK, but not internal hardware drivers since the installers don't recognize the OS.

If the computer booted to windows before you tried updating drivers, try reinstalling win 8. It is best to download the ISO file and burn a boot disk to install it. That would be a clean install and might work better. If it didn't work, you have to reinstall windows 7 and do a clean install.

PS Most users hate the new Windows 8.

I used the Dell package to load the driver for an old ATI chip ... worked fine.  Granted, the other PC's I tried it on did load it fine and only needed sound and chipset in some cases.