Mate foo123, I guess the hard disk drive under discussion is a 320 GB one, right ? Such a drive provides 298 GB storage space, that is the size of your Disk0 . So no space is lost , no more space is recoverable . For a better study, read
Where Are All My Gigs? .
As the unavailable capacity is similar to the other partition that you made, it makes you think that you are losing storage space; but it is not the fact. You are using your full storage.