Mobo not working.... kinda..

Hey guys, i've been reading the boards and i cannot find any posts that really relate to my problem so i decided to ask.

I'm putting together another PC for myself, the specs are:

Mobo: GA-7VTXE+
CPU: AMD XP 2400
RAM: 256Mb
PSU: 300W
(GFX Card is left out for now)

Ok, i have it out on my desk so im sure im not getting any case shorts, im trying to get this up and running with just the basics for now, and this is my problem.

I turn it on, and the CPU fan only twitches, its like it turns on, but turns itself off again within about half a second, same with the power LED.. that goes on, then off just like the fan.

the RAM LED on the mobo itself stays on while i have power running, but im not keeping it on to long infact the CPU may overheat with the fan not working.

I've tried various PSU's with it.

I'd be greatful for any help or suggestions, thanks in advance.