this tread is kind a bit old but I v got the same issue and I solved my problem here is what to do
this come from a currupt bios for me. All the fan is spinning I got light in my keyboard mousse dvd rom and diskdrive but the display won't open.
it can be different thing so try this to see if it help
first take out your ram and start the systeme "always take the main cord off the case before touching anything
on the motherboard"
if the systeme start making some "beep" its a good new so put back your ram .if you don't ear nothing ,maybe there is no case speaker or your motherboard might have a problem.
now unplugged your dvd/cd rom and start your system.if you see no change yet this is not the problem
after that try it whit your disk drive.
now look in your motherbord ,there suppose to be there "near the cpu" a 4 pin wire ,2 yellow and 2 black
see if it s connected properly.
if you have done all this and you dont found your problem, you should reset the motherboard
searche for a round batery on the mobo,take it out for almost 5 or 6 minutes no 10 minutes is better and don't forget to take out the main cord before.after you wait 10 good minutes put the mobo batery back and start the system to see what happen.
i hope you gonna solved your problem