|What makes you think you have lost 9Gbs? Drive space just doesn't disappear without a reason. |
Bear in mind that there are a lot of hidden files and folders within Windows that do not normally show up in Windows Explorer. Just counting the space taken by the files and folders you can see never gives you an accurate figure of how much space you are using. Then there is slack space to consider.
If the drive is formatted to Fat32 slack space is more likely to be a problem than with NTFS. Also Windows will only allow a maximum partition size of 32 Gbs with Fat32. Third party tools can go larger but the slack space starts to become a real problem then.
The first link only deals with file systems up to Fat32. NTFS uses a cluster size of 4Kbs which considerably reduces the slack space problem,