my motherboard is a gigabyte GA-Z77-HD3 and my video card is an xfx radeon hd 7850. This is my first build so im still new to this but i put everything together and when i turned on the computer for the first time no image showed up on the monitor. after looking for a solution all i could find is that my video card is fried (but the fan still turns on) or its my PSU (xfx pro 650w) i also tried using 3 other video cards and using a few of the same 6 pin plugs from my PSU. i am able to boot the computer and use it when there is no video card so im thinking it has something to do with the motherboard. thanks for any help.
1) boot into your BIOS (DEL key) with NO video card attached
2) change the graphics setting so "PCIe" is FIRST before iGPU or whatever it's called
3) Shut down the PC and Install the graphics card (then switch the monitor cable to the graphics card)
4) Boot your PC
5) Go to www.amd.com and download then install the drivers
*So your problem likely is that you keep booting to onboard graphics but have the monitor hooked up to the graphics card.
Also, if you still have the monitor hooked to the motherboard and the BIOS is properly set to boot PCIe first (your addon card), you'll still get nothing because it's sending the video signal through the addon card which you haven't hooked up to.
I had the same problem when I was building my computer. When everything was assembled it refused to post. When I took my video card out it posted.
I found out that these cards have to be secured into the motherboard really well. I had only used 1 screw to secure it and not 2. When I put 2 and tightened them both down it posted with the video card just fine.
A few weeks later I installed another hard drive and it refused to post again. The screw to secure the card had come just a little bit loose. I tightened it back in and everything was fine.