To solve the problem fast provide information about your PC's motherboard. Then, according to Allan's advice, you'll be able to find the beep codes and consequently identify the problem.
P.S. If beeps are short and frequent you could have a problem with your processor (overheating). However, I agree that possible problem could be with the graphics card, so if you're able to try another one do it. If it works, smth is wrong with your graphics card.