Sounds like something got corrupted within the executable stack, Adam. You may try running either "System Check" or "Scandisk" and get rid of any disk problems. Barring that, back up any data files you have and then completely uninstall Photoshop and reinstall it.
Sorry to hear about this! Hope you can get it fixed. Err...you don't suppose you got a virus on your computer, do you?
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Patience, my BUTT...I'm going to KILL something!!!