Yeah I just recently got my computer new graphics, GeForce FX5200 and Geforce 6200. I can install them but when I get them in my computer i cannot move the mouse or use the keyboard. So I restart it, then a message says Invaild mode like 600x200 or something? But i cannot change it to 1024x768 because the sceen is black.... They are both really nice cards and I need to know how to install them properly

Turn off your computer.
Open the case of the computer.
Make sure you're properly grounded before working on your computer or you can damage it.
Then place the Video card into the PCI-Express slot. (Shown below)

Then close your case again and turn the computer on.

I belive you can only have 1 of these cards in the computer at the same time though. (Please correct me if I'm wrong guys)
Hope this has been helpfull.

Regards,
Olrik

Could you tell us the make and model of this computer. If it's generic please let us know the make and model of the motherboard.

Do you have a user manual for this computer/motherboard? If yes, please consult it for the installation of two video cards.

There may be a white clip on the PCI-E 16x slot which you have to pull out to put the GFX Card in, When you push it in your should hear a 'click' which meens it has been seated properly.

The model is the E-3600 and its gateway ive got 1024MB of RAM and my page file says 485mb used 1975 avalibe

I can't find a user manual at Gateway. Besides, there is a whole range of e-3600, starting with very weak corporate edition going up to work stations under the same name.

It looks like like quite an old machine and I doubt if it can run two video cards. I guess that there is only one AGP slot and some PCI.

Honestly, I am not sure. Not enough data and too many guesses. Try to find your user manual for details or approach Gateway's support.