having some serious cpu issues

[breakingnews]

Alright, jokers, riddle me this:

I bought a Dell Dimension 4600 w/ P4 2.8 ghz, 800 mhz FSB, 256 MB RAM (I know, I know, I have a Dell, that's my first problem).

So about three or four weeks ago, I started up the computer and it wouldn't boot up. It powered up, and I could hear the fan blowing, but there's no signal to monitor, no power to peripherals (mouse, keyboard, USB wireless adapter, mem card reader).

Forced a shut down and tried to boot up maybe 5 or 6 more times. Finally it booted up as normal and worked fine.

Next time it wouldn't start up. Or the next time. Or the time after that.

The thing is, if I leave the computer in the stalled power-on mode for 5 or so minutes, it will boot itself up.

The Dell diagnostic lights in the rear say it's a memory problem. I ordered new RAM (which should be here, uh, yesterday), but I don't think that's the problem.

The motherboard power light is on, so it's being powered. Someone suggested that the board or the processor might be fried, but why would the computer work then? Is that possible?

My built-in network adapter, however, does NOT work. It shows both lights (green and orange), but does not pick up signals from my cable modem. I ran Time Warner's set-up CD and the diag program says it can't pick up a connection.

What's going on here? Is my computer totally fucked? I don't think any critical parts are broken, otherwise the effin' thing wouldn't start up.

Someone please spare me of my troubles!

-bn