Can I do ANYTHING to get my Nexus 7 2013 working again

[AC Question]

After a upgrade to 5.0 whatever all I get is the poor dead Android robot with the dreaded red exclamation point. I don't want to lose my files! I've tried pressing power/up buttons and even took off the cover and checked to see if the battery connection was loose. It wasn't, so I didn't touch anything else and put the cover back on. It was that latest Google update that killed it, I'm sure. But I don't want to lose my files if I can help it. I really LIKED my Nexus 7 and hate to lose it.