If it's not shutting down, just hold down power for 10 seconds to force a shutdown.
In the 'Get Info' window, don't pay much attention to the permissions down at the bottom. Mine says I can only read as well on the Mac HD.
If after the restart nothing has changed, I'd attempt to boot to Recovery Mode ( ⌘ + R at startup) and try to reinstall OS X. [How To]
Before reinstalling, it's always advised to make a backup of the system.
If after the reinstall nothing changes, I'd highly recommend just wiping the system if there's a backup and formatting the disk and changing the name in Disk Utility when you format the drive and migrating your data back over afterwards. [How To]
After the erase and reinstall, make sure the problem has gone away first before migrating any data. You'll also want to use Migration Assistant after the reinstall rather than migrating first in case that brings the problem back.