Will the wrong kind of power supply kill the motherboard and every thing connected to it ....or just the motherboard ?

I wanted to upgrade my Dell Optiplex GX280 (only 6 months old) power supply from the 305 watt to a 400watt, so I can run a 7800 Gt graphics card for high end games. Well I bought one on ebay...when it arrived, the main connection to the mobo, don't know what it's called, only that it is about a inch and a half in width that snaps on to the mobo. Well it wasn't the same size as the original (about 4 pins shorter)...but I forced it on any way, because the seller said it was compatible with the GX280. When I tried to power up ....nothing works. I re-installed the original power supply...and still nothing works. So now I'm wondering if the memory sticks, HDD, and other stuff connected to the mobo are "fried" (dead) ...or is it just the motherboard itself that needs to be replaced. Or will I need to just buy a whole new desktop PC...and make the Optiplex just a bad memory and learning experience?
Any help or advice will be appreciated ....write : ddavel544@gmail.com


Picture of Will the wrong kind of power supply kill the motherboard and every thing connected to it ....or just the motherboard ?
new on left original on right.jpg
original connection.jpg
Re-design7 years ago
did you force it really force it?  Or did you just find a combination of the shaped pins that fit.

If you forced it then you might have really damaged something.

If you found a combination where the pins fit without really forcing it then you should still be ok.  The computer that I'm typing right now has the same situation.  The plug does not have as many pins as the mother board.  If I remember right it's this one but I know that I've done it on one of mine before and it worked out all right but I did not FORCE anything.
ddavel544 (author)  Re-design7 years ago
Re-design, thanks for answering....Yes, I did have to push down on it really hard to get it to fit tight and flush with mobo connection. In fact, I did it twice...in the first picture there is a black arrow (blurred out by camera flash) on the power supply pins pointing: ------> so at first I connected it 4 pins to the right. Then the second time as you see in the pic. So, maybe your right I may have killed the mobo...but is the memory sticks,etc. affected as well?
Only way to tell is to test them in a computer that is working or take them to a computer repair shop that has a memory tester.