I attempted to install an nvidia graphic card and it showed up in device mgr. but my monitor indicated no signal found. I was advised to go in BIOS and disable on-board peripherals(set to auto) and reboot. Now I have NO display at all, just a black screen. I can't see to get back into BIOS to turn it back on. System boots and I try pressing F12, but see nothing to know if I'm in or not... It's a dell dimension 2350 w/win xp. I sincerely appreciate any- and everyone's help.

Hi,
The easiest way is to reset the BIOS. Remove the BIOS/motherboard battery for a few minutes (not seconds) and then replace. you should then be able to access the BIOS on boot.