Problems with video card installation

Hello,
I bought a video card and when I install it into the AGP support, the computer turns on, but nothing on the screen. All the fans is on, but no keyboard, no mouse...no beeps.
I put another video card at mine -same resultat- don,t work
I verified my video card in another computer, is ok.
The driver for onboard video card is disabled;
I installed the latest versions for BIOS and Chipsets.

The configuration is:
Mobo : Intel D865GBF
Proc: Pentium4
Power: Corsair VX550W
Video card: EVGA e GeForce7600GT Superclocked