Another space confusion query

I have a 4gb SanDisk Cruzer (SDCZ6-4096RB) that I bought several years ago. Its been great but I noticed recently that it says it has only 2.51 gb of free space and 1.22gb in use, but the only files/folders on the disc are system/US3 related (totaling 93.5 mb). I followed the advise given to another forum member to display hidden folders, but when I did that, I found no trash or other extraneous data folders–just a system folder with an Apps folder with 6 folders with alpha-numeric names following an 8-4-4-4-12 character sequence. I’ve used the drive between 3 computers in the home, all of which use Windows XP. Any ideas as to what to try to regain the missing 1gb of free space?

2.51 + 1.22 = 3.73,  which is .27 less than 4.00, so how do you think you’re missing 1GB of space?

The number of bytes a device has rarely equals the number of bytes of formated OS space.  Cluster format overhead and FATs use bytes also.

A more intriguing question is if 1.22 GB is used and the U3 system folder is 93.5 MB what’s allocated in the other 28.5 MB.  LaunchU3 is only 1.27 MB.

Let me try to clarify the situation again: 1.2 GB of space on the drive is indicated as “in use” even though the ONLY thing on the disc are systems files/US3 files. Somehow the disc thinks there is 1 GB of something on it even though there isn’t. A check of the hidden folders/files showed nothing that can account for the 1GB of missing space. I’m wondering if a system folder dealing with trash may have been deleted somehow. The drive is already formatted FAT32, but would reformatting do anything to recover the lost memory?