I just installed a Sapphire Radeon HD 3GB 7950 into my computer using Asus P8Z77-V LK motherboard. It wont detect the video card anywhere, I tried to find it in the Device Manager and it doesn't show up, I tried to install the AMD Flash Catalyst, but the install wont work and will not install any programs. I am using Windows 8. when I try to plug in the HDMI into the GPU it wont work, and I have tried to set the GPU as the primary graphics and it goes straight back into integrated when I reboot. Any help please.
Almost sounds like you don't have any power connectors plugged into the video card. There should be either two 6 pin power connectors, or one 6 pin and one 8 pin power connector plugged into your card from your power supply.
Maybe list the rest of your specs so we can help further. Make sure your PSU(power supply) is listed in your detailed specs.