No bios screen asrock z77 extreme6

I had a 3rd party pci-e video card installed Nvidia GTX 660 which was running fine.  I wanted to do some maintenance and booted into the bios and assigned the on board video as the primary and then rebooted and now I can't get video even to get back into the bios.  

The cable check idea above is valid of course, as well as removing the cable from the video card if you have a cable connected to both video sources.

Another possibility is your monitor is not set to auto-switch its input, if you are using a different cable type (DVI vs HDMI for example) with the onboard video. We ALL have been burned by that once or twice.

Otherwise, I suggest clearing the CMOS/BIOS and starting over. Your board has a Clear CMOS button on the IO panel, so you don't need to open the PC case.

Alright so I went home last night and made sure the display found the correct source and and still nothing.  Tried a second display via, DVI,VGA, and HDMI and nothing.   Also I pressed the clear CMOS button and nothing.   

Polymer wrote: I have a similar story. my motherboard is a z77 extreme4. I'm on windows 7, I disabled nvidia graphics and switched the dvi cable to the motherboard. It was Intel HD4000, and worked. I restarted my computer, but the screen was blank, though I could hear windows turning on. I reset my bios by taking out the battery, waiting a minute, and putting it back in (forgot there was a motherboard switch for this >_<). Now the computer doesn't boot, and the motherboard cycles through error codes, ending on A2. Thoughts on this would be great.

The A2 POST code is a SATA/drive issue, BUT as I recall with my Z77 Extreme4 board, when you are in the UEFI/BIOS, that is the code that is displayed, so not a problem.

Since you cleared the CMOS, you would normally see a message about pressing DEL, etc, to enter the UEFI or it will timeout and boot. In your case I bet the board went to the UEFI UI because you removed the battery, but you still have the display problem, so could not tell.

If your video card is still in the PC, the board thinks you are still using the video card, even without a cable connected to it.

Try removing the video card, which will force the use of the integrated graphics, regardless of the setting of Primary Graphics Adapter in Northbridge Configuration.

When (if) you get into the UEFI, check the setting of IGPU Multi-Monitor in Northbridge Configuration. The default is Enabled, which allows the IGPU and video card to operate at the same time. IMO, that setting can cause the problem you have when a video card is installed but no cable is connected to it. If you have the configuration again with the video card installed but all cables removed from it, set IGPU Multi-Monitor to Disabled when you set Primary Graphics Adapter to Onboard.