I'm about to install a new GeForce 6800GT 256MB AGP card into my PC and I was hoping if someone could give me some very simple pointers on the best way to go about this. It seems every time I try to mess with any display drivers (including the ATI drivers) for my 9250 I end up with a no Screens Found Error. Is there a good tutorial or something?
Also, I recently tried to move my 9250 to my fourth PCI slot instead of my first to make room for various things and I also got a No Screens Found error, citing an inability to find my video card, how can I fix this?

What distribution is this?

Do a search here at LQ for existing threads on the topic. Generally speaking though, the simplest way to do it is to go to the nVidia Linux Driver page, download the package, then follow the instructions listed. Overall it should be about a 2 minute process. Good luck with it

Mandriva 2007. Just now I wanted to see how fast my radeon was, so I installed the actual ATi drivers and it slowed it considerably and also set it at a really high resolution (1240x864 or something like that). Well, when i tried to open ATI Manager it wouldn't open, so I tried to change the resolution through Configure Your Computer and now I can't start X. It gives me the old no screen found error, along with something about the configured monitor matching up to the configured screen. I'll post the actual error message if need be, but any help would be much appreciated.