If you're getting 8 beeps, then there is a problem with the graphics device. If you don't have a video card, then it means the integrated graphics chip on the motherboard is probably fried and you'll have to either replace the motherboard or install a graphics card to handle video output. If you have a graphics card installed, then as it says, try reseating it, and double check that any external power connectors for the card are firmly in place (if it needs them). If that doesn't work, then the graphics card is probably faulty and needs to be replaced.