1 long continuous beep most of the time means it's a memory problem. Try moving your RAM stick into the 2nd or 3rd slot.
If that doesn't fix your problem, make sure your RAM is ok by
using it on a working pc.
If you can confirm that your RAM is ok, then try reseatting your vid card or try a different "working" vid card. If it's not the vid card, then it's your mobo.