Reset bios by pulling the battery again.  This time it worked! Was able to enter F2 and setup Corrected entries to Legacy again. Booted into windows. Thanks!
I entered F2 into BIOS settings.  Changed Legacy to UEFI and Legacy disable and secure boot. Restarted and no display. Power switch steady white. Green blinking LSI.   Some disk activity light.   Keyboard and mouse light up. Power supply test green.  Reset BIOS with jumper, no display.  Removed cmos battery. Tested 2.99 Vdc. Installed back into board. No display.   Ctrl + Esc held down, no display.  Tested with one memory stick  on both cpu's. No display. System had been working great.  Please help. How can I brick this by changing the bios?    
T7910 Changed from legacy to UEFI selection in BIOS and computer will not boot, 
no display