Are you sure it's a geodatabase? What flavor? When you say it shows up in windows explorer, what does it show up as: a microsoft access file (mdb) or a directory (gdb)?
A personal geodatabase is an access database on steroids and it carries the extension of .mdb. Nothing more, nothing less. Just an access database with a bunch of extra tables built in so it works geographically.
A file geodatabase is a proprietary database by ESRI and it carries the extention of .gdb; it will show up in windows explorer as a directory with a bunch of meaningless files inside it when you expand the directory.
