can't access app store to update iOS
MBP froze, wouldn't restart or shut down. Forced shut down with power button. after restarting, most of application icons are question marks (?) and are non functional. i can't access the app store to update my iOS from 10.9.5 to 10.10. can anyone help or point me in the right direction to resolving this issue?
MacBook Pro, OS X Mavericks (10.9.5), mid 2012 MBP