Windows 7: Desktop will not boot when I have new Power Supply

Interesting, Let make get a confirmation, i do not believe you need a POWER LED.
As long as your POWER SW(power switch) is connected where it belongs this should not be a problem. You would only need POWER LED if your computer case has a light in the front that displays if its on or off.

The Power Switch is all that is needed for the computer to start, The power led is the led light that tays on when the computer is on, the HDD led only shows when the hard drive is being accessed. None of these is nessary for the computer to start, only the power SW.

Make sure all connections on the motherboard are connected and seated all the way, take all ram out and start the computer. It will not start without ram, but if the motherboard is acting properly, you should hear a serise of beeps, to tell you there is no ram. But, be sure tof the connections. When changing ram it is quite easy to accidentially bump and loosen a connection. We have all done it.

If pressing the power Button does nothing, even though the board reports recieving power, its likely a connection issue.
One way to know for sure is if your board has jumper switches, or onboard switches to bypass it entirely. Which it may not have.


As metioned, the ones marked LED will be for indicator lights. The PC will function correctly with or without them. They are not critical.
This is also dependent on the Case itself. though many have them, not all will. Some may only have the HD LED, the Power LED, Both, or none at all.



Take a close look at your front panel connectors. they look similar to this:

These are from the case, specifically the power switch etc, connecting to the motherboard.

The motherboard itself should have connections similar to this:


Keep in mind this is an example and may not be exactly what you will see.
The important thing is to look closely at the motherboard as these will be labled.
Match the wires (note the + and -) and make sure the connect at the appropriate place.


Also, double check that the long, 24pin main power connection is connected securly. Typically on the far right side of the motherboard.
And also, check the CPU power connection. This will likely be a small 4 pin (square) connector, or maybe even a 8pin. This is usually on the top left area of the motherboard, left of the main CPU area.


Any time you are working with changing anything inside the case, you should ALWAYS make sure the PSU is unplugged from the wall, flip the switch on the back, and then power up to drain any exceess power in the system before you touch anything.

That goes for everything. Changing RAM, reseating GPU, adding a sound card, or even reseating power connections.

i dont have none of those though but there's a blue light in the front of the tower and orange color on the button of the tower in the front but supposed to be on which it's not.

old psu has no power switch which is steady green on the back of the psu while new one has a switch but no light... the only time there's a light is if the computer is turned on.

I remember having some green jumper but not sure where it is... when i never put it back on, it still works but now it doesn't when i changed rams etc....

I am sorry i don't quite understand your post.
Any chance you can take a picture and upload it ?
Screenshots and Files - Upload and Post in Seven Forums

So far your tower has a blue light and a orange light? Can you take a picture of these?
Old psu doesnt have a power switch but a green light in back. New PSU doesnt have a light but has a switch.

What is this green jumper your talking about ?

Did you mess around with the front panel connecters? (also take a picture of this)

Blue light for power led
Orange light for hard drive









ignore the red and blue lights since taking this pictures using PS3 eyetoy cam on laptop

The red light on picture 4 is that from the PS Eye Cam?
Sadly these pictures wont help us.

Sorry but if you follow of all Wishmasters suggestions on post 13, I think we reach the end of the road, We either go back and retry a few steps and double check everything we mention was done.

Intrusion switch connector.... what is that and that's the one with two pins that not connected

The intrusion connector is usually a connection to BIOS that will tell you if the case has been opened. It is not necessary.

update - when i plug the power supply cord back in then pull the plug out, it made that power down sound but the computer remain non bootable