Bug? Computer Freeze caused errors on next load

My pc locked up solid, I was not in the middle of editing anything, maybe pushing it to my phone, I can't remember.

I got a bunch of errors saying:

An error occurred.
The given key was not present in the dictionary.

A bunch of classes were missing from my project.
Attempting to add existing classes that were missing gives me the same error.
The bas files are empty.

Luckily i had system restore in windows 7 enabled so I could restore from 'previous versions' tab. For anyone who's doesn't have that enabled in system properties of my computer, you really should. I know versioning systems help, but this is another automatic copy.

I just restored about 1/2 of my .bas files and the project opened correctly. For some reason mostly files I hadn't updated in about 2 weeks were affected, and the ones I edited today were not affected/corrupted.

Correction, I had to re-add the modules to my project. But they add correctly now in the IDE. Now it compiled ok.