I've had my computer for about four years. It worked as intended until early today, when I tried to turn it on and I noticed that the mobo beeped unusually and I'd get no signal on my monitor. Everything else powers up, fans, cd drives and I can also hear the hard drives. The computer sounds as if it boots correctly, but I get no monitor signal. I tried looking through Intel's documentation for my mobo but I just couldn't find a beep or POST table. I get a long beep (3 seconds) plus two short beeps that last about half a second each. I usually get a single one second beep. Help appreciated.