If what you want is to reset the BIOS, try to disconnect the battery of the mainboard, or use the bios reset jumper, usually near the battery or the BIOS chip, and move th ejumper, power on the computer, wait for 5 seconds, power it down, setthe jumper to the original position, and the reset is done.
Enabling video in BIOS: When you boot the PC you should get a message saying to press X (usually F1 or Del)to enter setup. This will take you to the CMOS and BIOS configuration screens. Depending on the PC and BIOS version, your card can be enabled from here (you’ll have to look through the screens because they vary in different pc’s).
2) I assume that it wasn’t disabled due to a conflict, if it was, go to Control Panel>System and check that you have no conflicts and try updating the card’s drivers.
NOTE: When performing BIOS updates, the system should ask if you want to save your old BIOS for restore purposes, SAY YES!
Rerunning the BIOS setup will allow you to revert to older versions if needed.