Motherboard light is on but computer won't power up.

Apexklutch

Honorable
Sep 14, 2012
5
0
10,510
My computer has been acting wierd for the last few months. When I went to install a new motherboard and CPU it would only start up if I quickly flipped the power switch on the back up and down. That worked for a few months up to recently and now nothing I do will power up the computer. I don't think it's the power supply because the computer has powered on correctly for the last few months with no problem. The motherboard light is on so does that mean it's a problem with the case? or something else? Thanks for any help.