First thing, those beeps from the mobo are codes for an error. You need to write down the beeps as you hear them, they may be long beeps, short beeps or a mixture of the two but you need to write them down.
Next what make of mobo is it, or even better what BIOS is on the mobo?
As a total guess I would say your memory is kapput or dislodged, try removing it and reseating or try putting it in another memory slot, also reseat all AGP and PCI cards.
If that doesnt work report back with the beep codes and your mobo or BIOS info.