Did you allow Lightroom 5 to upgrade the LR 2 catalog, or did you re-import all your photos into Lightroom 5?
I am not too sure, I think I just re-imported the photo's
Start a new Lightroom catalog, use File->New Catalog
Then opne the Lightroom 2 catalog, use File->Open Catalog and point to the Lightroom 2 catalog file. If LR5 asks you if you want to upgrade the catalog to LR5, say YES or OK or whatever is the affirmative response.