Ugh. Good point. The first thing Dell - and Dell Support in particular - will
always tell you to do is to reformat your drive. That's almost always the
worst possible thing to tell somebody right off the bat and there are
typically ways to fix things and not lose all your data. But saying that
makes life a lot easier for them and keeps their support costs down, which is
the main reason they do it undoubtedly.
I'd Google around and do some research on data recovery to see what might be
possible. And while you're doing that -> don't write anything to your problem
disk, you might be overwriting some files you want to keep. Windows resets
pointers to deleted files but keeps the actual data intact, but it marks that
space as being available for writing so another file can use the space if it
needs it.