Graphics card issue

[Cyberlinkist]

Heya, so I got a graphics card I want to try. I have no real experience with this kind of thing, but I managed to install a new power supply and get everything hooked up no problem. The problem I have now is this; If I plug in the card I don't get a display on either the built in board or the graphics card.

The graphics card is an XFX Radeon 6950 HD 2gb

My onboard is an AMD 760G

When I plug the graphics card in and power up, everything seems fine on the hardware. The computer acts just like it does when its on normally, but neither the regular HDMI port nor the HDMI port on the card itself gives me a display. The weird thing is when I unseat the graphics card and keep the power plugged into it, the onboard HDMI port works fine, it just seems like having it connected disables it and also doesnt work. I'm sure this is something dumb I'm not getting, but if anyone has it in their heart to help a n00bie I'd appreciate it

 

[Laquer Head]

You might need to just go into your BIOS and enable the GPU setting so it knows your using external instead of off the mainboard. Some boards don't require this manual change, some do. My old MSI Gaming 3 Z97 board, for example, you had to go in a manually change the setting or an external GPU wouldn't work, giving you black screen.

What motherboard do you have (make/model)?