Mac Mini hard drive erased?

i upgraded memory in 2011 mac mini , when booted gone. can't lion run. stuck on mac os x utilities page. on earth have happened erase , start me over. do here? dont have backup on time machine , can't find wireless signal reboot lion. please help!

 

some additional information may help. computer not shutting down held down power button until shut down on macbook. have possibly caused erase , restart?

 

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