Z77-UD5H BIOS playing up after using Easytune

[Stainless]

My Z77-UD5H mobo had been working just fine. BIOS F7 and all stable (keyboard and mouse work just fine in navigating the BIOS).

I decided to use Gigabyte's Easytune, which seemed to work. However, after its use, I find I can now no longer access the BIOS, although the system boots up just fine. No matter which BIOS screen choice I make, all I get is a blue screen with the BIOS title at the top and an unusable mouse pointer.

The same thing happens with the backup BIOS.

The same thing happens (both BIOS) when I clear the cmos (although I know default settng have been set as I've now lost the Intel Rapid Start).

The same thing happens after I uninstall Easytune (just in case that was doing something).

Any thoughts on what may have happened and how to fix it?

Thanks in advance.

[wazza300]

try a longer cmos clear by taking out mb battery for 30mins,maybe overnight, depends,then put back in,load optimised defaults and try

when the battery is out power off at rear of psu or unplug from wall socket and pres and hold in the front panel power switch to fully discharge the mb of power

[Stainless]

Update.

On a hunch, I unplugged all of my rear USB plugs from devices, other than my keyboard and mouse. After that, the BIOS worked. It looks like the BIOS becomes non-functional if you have any USB device plugged into the rear panel USB2 extension.

[boondocks]

Try updating drivers, not sure if the Gigabyte download site has newest or not, look at the links at top of forum. Some people have had problems with USB, most seem to be cured with newest BIOS, drivers as far as I can tell. At least mine seem OK.
I'm using the USB 3.0 front bracket that came with the board plugged into the first Intel Header (_1) for stuff like flash drives and it seems to be alright.
My wireless KB/mouse I've used in most of the rear ports with no problems.