System won't boot

Hello,





I have ....zx series 945 board, 3 GHz pentium 4 processor, 1 gb DDR2 RAM.
last time I properly shutdown my pc.
when I try to start again it won't start.
(( all fans are working) fine but moniter light shows red, normally it terns green on startup.
so I jst open all parts of system n remove all dust.
I tried another Power supply a new SMPS but nothing different. When I remove my RAM n starts pc no sound,also tried my ram in another slot.

unable to diagnos its problem pls help.
is it possible that some CPU don't make sound on removing Ram or there is all problem is with my motherboard...may be its display...do we have any procedure to check my board.