Ok im fairly good at knowing what wrong with a computer but this perplexes me, my computer powers up but it doesn't boot, i started from step 1 everything out processor mobo and hdd nothing else expt the power cords, the LCD says that it receiving signal because when you unplug it says, no DVI, ive tried removing th RAM nothing, one stick at time nothin, jsut teh same old process of turning on but no display, the HDD light dosn't go on tho, but i can hear it working is there anything im missing, ohh yeah the PSu is fin i tested it wiht one of those testers, HDD works in my other desktop, only thing ive changed is the case and that's like yesterday, soo someone tell me what im doing wrong or if its time to invest into a new motherboard?

Specs,
intel quad Q6600 @2.66 stock
8 gigs pc6400 ddr2
NEW haf 922 case
500 gb westerdigi(1 tb exteranl)
win 7 ulti
some dinky old Cd player
readon hd 5770
Intel DG35EC how sad my motherboard is like soo old

can you hear some sounds, when you turn it on ? (MOBO speaker)

no its fine i tested all teh CAP's and it seens one of them was defective so i got a new motherboard and i got my think clocked at 3.8Ghz :D