No post beep, monitor wont turn on

hi,
I am having a problem with my pc. About a week ago i came home and turned on my desktop, it started up as normal but then about seconds in it shut down. I tried turning it back on but there was not the normal startup beep and the monitor and keyboard did not turn on, but the drives and fans and everything else doesinside. My computer has a abit-ul8 motherboard and is custom built. The only time i can get a beep is when for i change something inside it like removing all the ram and pulling out my grapics card. I have read it may be a bad motherboard, but i want to know if there is something else i can do to get it working again.
Thanks