Question optiplex 7010 pc turns on, power button blinks orange and theirs no display output whatsoever

[42xdus]

it all started after I put my bios on legacy

 

[stonecarver]

Unplug computer

Unplug Hard drive

Remove battery for 5-10 minutes

install battery

restart computer without Hard Drive installed

Go into BIOS Re set to UEFI save exit

Unplug Computer

reinstall Hard Drive

Plug back in computer

Restart computer