RecycleBin is empty yet drive still shows storage in use

On a Windows 2008 R2 EE server, I have a G drive, and it had an Exchange 2010 database on it. I removed the DB from Exchange, and I proceeded to remove the DB and other files from the G drive.

I answered yes to permanently deleting the DB file since it is too big to recover. 

After emptying the RecycleBin, I noticed that the G drive still had 20GB in use.  I don't see anything.

When I looked at the Shadow Copy tab, I see 20GB in use, but I don't have Shadow Copy enabled.

Any suggestions?

Thanks

Ron