PC Not Working after installing new heatsink

[DatMac]

I've had my custom-build for around a month now. Recently I wanted to start overclocking so I bought a new heatsink. I took the mobo out of the PC and installed the new heatsink. I was very careful and grounded myself. When I was done I put it back in the case and pressed the button. The fans didn't spin or anything. So I changed some cables around and now this happens:

The HDDs spin up
All the fans work
The new cooler works
The DVD Drive works

But I can't get the case speaker or video to work for the life of me. The graphics card is a Nvidia GTX 550 TI. I thought it might be the CPU, but I'm not sure. Any help is appreciated, Thanks!

 

[clutchc]

Changed some cables around? They only work one way. You better check your wiring. What board and cpu do you have?

 

[twelve25]

Well it seems fairly obvious you missed something. Triple-check everything. Reseat RAM and Cards, check ALL cable connections.

 

[DatMac]

Board: GIGABYTE GA-MA790XT-UD4P AM3 DDR3 AMD 790X ATX AMD Motherboard
CPU: AMD Phenom II 955 BE

Thanks for the replies!

 

[clutchc]

Do you have access to the board's instruction manual for the wiring? If not you can download a manual here: http://www.gigabyte.com/products/product-page.aspx?pid=3010#dl

The case speaker might be in reverse. Blk is + and Red is -
Did you remember to plug in the PCIe cable to the card?
CPUs are pretty dependable. That would be the last item I'd expect to fail.
What is that add-on bracket that's shown with 2 ports and a Molex socket? Powered eSata?