Q: iPhoto frozen in full screen mode

Can you get out of full-screen mode? If so, do that, then quit and relaunch.

Please read this whole message before doing anything.
  
This procedure is a diagnostic test. It won’t solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
   
The purpose of this test is to determine whether the problem is localized to your user account. Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”
   
While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.
   
Test while logged in as Guest. You'll have to hold down the option key while launching iPhoto in order to select the libaray. Same problem?
     
After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.
  
*Note: If you’ve activated “Find My Mac” or FileVault in OS X 10.7 or later, then you can’t enable the Guest account. The "Guest User" login created by "Find My Mac" is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.

Launch iPhoto in your account while holding down the option key. Click Create New... in the dialog that opens and create a new library in your home folder. Does the same thing happen? After testing, you can delete the library you created.

You have the following options:

Restore the iPhoto library from the most recent backup that predates the issue.

Repair or rebuild the library.

Scavenge the library with iPhoto Library Manager independently of iPhoto (Library ▹ Rebuild). Books, calendars, and slideshows won't be preserved.