Built my PC, it turns on but doesnt show up on monitor?

[Carllll]

Hi guys this is my first build and I am having problems with turning it on, all the fans turn on and rotate but it does not sound like the motherboard and processor are actually starting up (even though all the fans in the gfx card and processor work fine).

What should I do? I'm at complete ends and my warranty ran out on it all today so I cannot return it.

I have an AMD 8-core with corsair 8gb of Ram, a 2TB Hard drive and Gigabyte SKT-AM3+ 970A-DS3 FX 3.1 Motherboard with a XFX ATI Radeon HD6850

 

[FinneousPJ]

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems

 

[Carllll]

I've been through it, spent several weeks and still at ends.

 

[FinneousPJ]

Oh, sorry. I think it is customary to state "I looked at the stickies and used search and it didn't help." if you've done that

What is your PSU?

 

[timbob13]

A couple things to check:
-There is a 4-pin/8-pin (yellow and black) that must be plugged in, aside from the 24-pin. This is easy to overlook. it's between the port shield and the processor
-Memory in the wrong first slot can halt boot-up
-plugging in to the on-board video (if your motherboard has it) when using a dedicated card will result in nothing appearing on the screen.