PC Tower Light Turns On but Nothing Else

[Gorgod]

I recently purchased a new graphics card to replace my old and outdated one. After installing it and turning it on it didn't work, but then I realized that my psu did not meet the requirements of the graphics card (GeForce gtx 650 ti). So I promptly removed the graphics card and put in my old one, but it still did not turn on and only the pc tower "on" light appeared. No fans, humming, nothing. This made me believe that I had shorted out my power supply by turning it on with the graphics card in, so I bought a new power supply as I needed one anyway. I returned home, installed the power supply, and STILL it would not turn on. not only that, but i cant turn it off by pressing the power button on the tower, i have to turn off the power. i had the same problem with my laptop a couple months back, and that resulted in me buying this computer, but with that it seemed like a problem with the motherboard. I opened up the case and started it and saw a green light appear on the motherboard when I turned it on. Does this rule out the possibility of a damaged motherboard, because frankly that's the only thing that I could think of that would be wrong with it. Any ideas?

 

[Fritz 125]

If you gave us your specs maybe the nice people of this forum could help