Don't disable Legacy Boot if you don't have a Nvidia 600 series card with UEFI firmware on it.
Hold down power button for 3-4 seconds and release to get back into firmware settings.
Hold the power button down 3-4 seconds at any old time? Should I have my GPU still plugged in and monitors hooked to that? Or should I hook the HDMI up to the onboard?
Hmm.. wtf i just noticed that my reply appeared several times in row. Deleted the duplicated now.
If you have your PCI-E GPU plugged in then press power button, hold it for 3-4 seconds and release and it will take you into firmware settings or you can use IGP instead and then you don't need to hold power button because the IGP works with Legacy Boot disabled. IGP has UEFI firmware. Note that IGP must be enabled in the firmware settings before you can use it, if it is set to disabled then you must hold power button & release.
When I hold the power button while booting the motherboard beeps with error code "10" being displayed on the motherboard. If I hold it while shutting down, the PC will shut off and then restart but still with nothing being displayed. I tried the integrated and I tried the GPU as well.
I found the following link on recovering the BIOS
I followed the directions on there to recover the BIOS with a USB drive. It worked on my 2nd attempt.
Thanks for the replies!
I had a very similar problem.
You cannot disable Legacy if you did not install Windows 8 as UEFI and went through a procedure. You can check to see what your windows install is by doing a Windows key + R and typing: msinfo32
Under BIOS Mode, check to see if its UEFI or Legacy.
If its Legacy and you want UEFI, you need to re-install using a UEFI Boot disk or an original windows 8 DVD that has UEFI on it.
If your BIOS Mode is Legacy and you try to disable Legacy, your computer wont even post. Happened to me. I needed to press the square button that lights up red on the back of the MB to be able to boot back into BIOS and enable Legacy.
Also make sure your video card is UPDATED with the latest BIOS so it can boot into UEFI. I had a nightmare last night trying to install Windows 8 UEFI with an outdated BIOS on my GTX660 TI. I had enabled my IGP to always be on in the BIOS. But when I booted up, I only got video on my monitor through the HDMI cable connected from my MB to monitor. And then once I logged in, i would get video from my GTX660 TI GPU. So it was weird, if i had my monitor set to the DVI input from my Video Card, when I started my computer, the screen would look black for a few seconds while computer booted up in the background and then suddenly just turn on at login screen. It was because it was displaying all the post info through the HDMI (IGP) and then kicking into the GPU. So make sure you have an updated BIOS on Video Card and that it supports UEFI.
Hope this helps. Now to go make another post about trying to go make Secure Boot work