Installed new power supply, computer wont turn on

[Genome]

So I installed a new power supply in my computer. I started it up everything was fine and working. I remembered I forgot to plugin the wire to my memory card reader. I open it back up, and see I dont have another wire for it. I see one that is plugged on the motherboard. So I unplug that, and connect it to my sd card reader to confirm that is the wire I need for that. So I connect that back to the spot on the motherboard. Now I thurn on the computer, nothing happens.

I try a bunch of things but nothing works. I take out the new power supply, and put back in the old one. It still does not turn on. So I know it's not the new power supply that is the problem. The old power supply was fine before I installed the new one. I must have screwed someting up. I mean it turned on and worked perfectly the first time with the new PSU. The only thing I did was unplug that wire on the motherboard and plug it back in. Does anyone have any idea on what the problem is?

 

[Mitch?]

Here's a quick checklist for ya.
20 (or 24 pin) motherboard connector. plugs in near RAM slots on mobo.
4 (or 8) pin CPU +12v connector. plugs in near CPU somewhere on mobo.
possibly a 4 pin molex (standard) connector into your motherboard, varies from board to board.
4 pin molex or 5 pin sata power to hard drives and optical drives.
optional - 4 pin molex to case fans, or case fans 3 pin to motherboard.
optional, depending on what card you have - 6 (or 8) pin graphics connector. looks similar to the CPU +12v connector. mid/high end cards will require a connector, because they can't run solely of the motherboard's power.
after this make sure the back of your PSU is turned on (there's generally a switch by the cord plugin).

 

[Candy]

Is your computer connected to some sort of power board? Or surge protector or anything? If it is hit the reset button and try, I know that sounds really simple but the same thing happened to me when I installed my new one and that's all the problem was.

 

[Genome]

Could this be the problem? On my 24 pin connector (I have on where the last 4 pins break off if you only need 20), on one of the top ones, there is no metal ring/part on the inside of the pin. On my old PSU, on my 24 pin connector, on the same spot, there is no metal ring/part on the inside. Could it be that it came off while unplugging both PSU's from that connector on the motherboard?

 

[Genome]

Could this be the problem? On my 24 pin connector (I have on where the last 4 pins break off if you only need 20), on one of the top ones, there is no metal ring/part on the inside of the pin. On my old PSU, on my 24 pin connector, on the same spot, there is no metal ring/part on the inside. Could it be that it came off while unplugging both PSU's from that connector on the motherboard?

I checked and there is not even a wire connected to that hole on the 20 pin connector on the new PSU and on the old PSU. I opened up this computer (my old one), and on that 20 pin connector, there are all wires connected to that with all the metal insides on them. On my new PSU, there are two wires connected to one hole on that 20 pin connector? So my new PSU is supposed to be that way?

 

[fmw]

It sounds like you don't have the case power switch connected to the mainboard. You might check that.

 

[m3incorp]

Then you try putting the two wires that you unplugged back like you originally had them? Sounds like that wire you unplugged just might have been the case power button. Is switch set correctly on PSU (might have bumped the voltage settings, Power switch on PSU completely depressed to the on position) Does the PSU fan come on?