Your power supply might be dead, try using other PSU.
Originally Posted by LembasBread
His mobo is getting power, hence the green light, but it may still be psu related. Try things component by component to find out the problem. Check your case jumpers to make sure that power button works.
Originally Posted by LudaMan
If the psu was working fine, then the fans would definetly come on. If your fans arent working then it is DEFINETLY a psu problem.
Originally Posted by Syrillian
Test the 12V and 5V rail with a multi-meter. You will have to jump the PSU (pins 14 & 15...I think...its the green one and of the Black grnd wires on either side.)
Your fans may still spin, but there might not be enough voltage in the line to kick everything on....