mac mini not booting after yosemite

Just updated to Yosemite , but on rebooting it keeps powering off after 10% of the line moving across the screen

I cant even press OPTION R or even OPTION , Tried plugging in LION recovery USB but cant bring up boot selection

Kb is wireless Bluetooth .. But also tested with Windows USB keyboard , Holding ALT and CONTROL separately and together over and over again to try and get a response But no power seems to be sent via USB ports .

Its dead .. HELP .. I have a time machine backup so not worried about losing it all .. just how do i get to recovery ?