|Nothing you have said so far gives any assurance the graphics card is your problem.|
Q? Is this a desktop or laptop system? Presume a desktop.
Does it have a separate graphics card or is the graphics integrated in the motherboard?
You say it powers on but does it give any BIOS POST Beep?
You may have a powersupply failure, as well as ram or CPU failure.
Please provide a full description of the system including model numbers for motherboard, powersupply and graphics card if applicable.
Goin' Fishin' (Some day)