This problem might be related to the BIOS chip, try to update it to the latest but at this stage perform BIOS recovery to the latest version.
This is 0066
Once you download the .bio file, place it onto an USB flash drive and remove BIOS jumper on the board.. and power back up.
See here for instructions:
Hhmmm, I've never seen this before. Here's what I want you do to:
1. Unplug the system from the wall.
2. Remove the CR2032 Battery from the board.
3. Wait 15 minutes.
4. Reinstall battery.
5. Move BIOS Configuration jumper (labelled BIOS CFG) from the Normal position to the Config position.
6. Plug system back in and press power button.
This should get you into BIOS setup. If it does, make sure you do a full Restore Defaults operation and that you exit with save...
I just had another thought - this problem could be caused by a bad DIMM. have you tried using a different one?
I am experiencing the exact same issue with my new computer build using DZ77GAL-70K board.
I am running the latest BIOS version 66, have also tried 3 or 4 other previous versions of the BIOS without any luck. When pressing F2 for BIOS setup during POST I am not able to access BIOS using HDMI which is connected to a 55" LG TV . Tried with both the onboard HDMI and HDMI on a ATI 6790 pci-e card. If I plug a regular LED monitor in to the 6790 card with a DVI cable, it works perfectly fine...so why does this board have issues booting the BIOS over HDMI?
I have tried clearing the CMOS by leaving the battery out for several hours, the boot-to bios button on the back, and BIOS configuration jumper with the same result for all, there is no way I can get the BIOS setup to work on HDMI the board just reboots if I try to access BIOS.
Are there any fixes for this yet other than changing the monitor? Have never experienced this issue with any other board I have ever tried. Is it possible to set the Classic BIOS mode as the default setup? Maybe it is an issue with HDMI booting into the visual bios??
I have tried with a monitor using DVI port on external PCI express video card and yes it works fine, unfortunately for me, this is a bit of a pain because I only use a TV as my monitor for this computer. I understand since that is not the norm for a display there could be problems but I am wondering if any existing BIOS versions exist where resolutions other than 1024X768 are supported or if it will ever be included in a future release, or even a way to manually change in the BIOS what kind of resolution to use? I have used many other computers with different components to this same TV before using HDMI and never experienced this issue until the DZ77GA-70K board
For now I need to carry a monitor over to my desktop anytime I need to change a bios setting or overclock..it works but...definitely not ideal.