|Flashing green light on power supply usually means that the power supply is fried or there is a short in the motherboard.|
First thing to try:
1. With the power cord still connected to the power supply, unplug the 24pin connector to the motherboard and then replug it in to see if the short goes away.
Test the power supply:
2. If you have a volt meter, you can perform the following test on it: http://pcsupport.about.com/od/toolsofthetrade/ht/power-supply-test-multimeter.htm
3. If not, the easiest way to test everything is to purchase a power supply from Compusa or Best buy that has the same watts or more. Install it on the computer and see if it works.
Computer Repair Fort Lauderdale