PC starts then stops

hi. i uh recently got a Abit pc ISG-E2G
and last night it worked fine, perfectly infact. but this morning when i came to turn it on, it started up, and immediatly turned itself off..and i dont know whats going on so i changed the chords, blew on crap like a beginner would and tried again. same result, i moved it somewhere else, and plugged it in, it worked for a bit longer, but not long enough to get into XP. and turned itself off. i dont know the problem and its really annoying me, has anyone got any ideas??