eclipse - lost project


I have been working on a project in eclipse. I decided to back up the
directory that I was working on by duplicating the directory with a
date on the folder...

The problem was that I accidentally renamed the folder, instead of
duplicating it.

When I opened up eclipse, the project was listed as not found... DUH!
So I recopied the folder back to the original structure that it was in
for eclipse. Then reopened eclipse.

Oddly enough, the project still is not found! The directory structure
is in place! Is there some easy way to correct this?