I have a mobo with Gforce 8600 gt installed and 4 gigs of ram. Everything is plugged in and getting power, i know this cause the fans are running, but when i press the power button on the front of my computer, the whole thing stops working, and it wont start unless i unplug it and plug it back in. i cant think of why this would happen. My mobo is MSI K9A2 CF
Change those wires around ,make sure the reset switch is not being use for the start button.
And also make sure that the Power LED wire is not connected to the Power SW connector.
I think i figured out the problem. The thing was running but no visual on screen. I assumed it was the oben box gfx card i bought. I bought a new card and rma’d the old one. Once I get that… I’ll post an update. Hopefully everything works out.
Good luck 
[ot]Moved the thread to General Hardware.[/ot]