Seems to me you have a bug

No such thing as 47,000 files which went corrupt.

Sure you don't have a virus ?

I once had (ACDSee v4.0) that too many files were loaded in the program, and it couldn't make any more thumbs.

I removed my "ImageDB.ddf" and everything was fine again.

(but every jpg. must be rebuild.)

do a serious virusscan

remove ImageDB.ddf

uninstall ACDSee

reinstall windows, on top of the previous (and make sure your pics are in a non-system-folder).

But anyhow ... if you burn your images on CDrom ... you can see them again, once your system is full functional again.

Good luck

lhwipken.