PC Wont boot no beeps too

[Lilpok]

My pc wont boot. psu fan is running, cpu fan is running, when connect the 4pin to the mobo the power light goes off and when disconnect turns green but still cant boot. hard disk is not spinning
pls what may the problem. please mail me on poksam19@gmail.com
Thank You

 

[Emerald]

disconnect the hard drive, and any usb devices (not keyboard and mouse), take out the memory, and video card (if possible), and see if you get it to beep.

put the memory back in and boot again.

add video card back in and boot again.