When I run into this, I try to uninstall and reinstall Ps. It also helps to remove your preferences. It's like a fresh start.
Hope this helps!
Try trashing your Photoshop preferences, if you can't do it in Preferences because the application won't open, try this:
Close and relaunch Photoshop, and IMMEDIATELY hold down Ctrl + Alt + Shift (Windows) or Cmd + Ctrl + Opt + Shift (Mac), and respond in the affirmative to the dialog asking if you really want to replace the preferences. You must be extremely fast on the keyboard (if you don’t see the confirmation prompt, you were too slow).
You may need to do this a couple of times before getting the hang of it!