PSU TESTER? PG LIGHT

Could be the psu, could be the tester.
Got a DMM ?
Turn of the switch, jump the green Power_on pin with one of the Black grounds, turn on the switch, the psu should start.
Now use the DMM to check the Power_OK pin ( red probe to gray wire , black to ground ) it should read 5v

i have no clue what you are saying?

are you talking about on my mobo? and where would that be on a p5n-e sli

I'm talking about the 20/24 pin main connector that you plugged into your psu tester.

Another P5N-E SLI user, mine son is using mine  

yeah i defently dont have a digital multimeter, yeah its a nice board, i just bought another power supply hopefully its because of the PG and not the board

as in bought, i just bought it online maybe 15 mins ago so i wont find out for a couple of days if that was the problem  

There are two basic kinds of consumer PSU testers: those with LED's (like yours) and those for about $10 more with a digital display.

The problem with the LED testers is that if an LED does not come on, you do not know if the voltage is missing or if it is a little out of tolerance.

The PG (Power Good) signal is a control signal that is supposed to go from 0 volts to 5 volts once all the voltages are present and in tolerance. This is supposed to take less than .5 seconds. The CPU needs this signal to boot.

You can monitor all the voltages from the back of the main power connector with a digital multimeter. Put the black lead on the chassis ground or a black wire.

Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.