No memory on flash drive

Windows (Windows 7 Ultimate 32-bit with newest updates installed) keeps showing only 5MB free of my Kingston 8GB flash-drive, but actually there is only ~4.05GB used (some kind of paradox). Here are some screenshots:

All items in the flash drive (no hidden files as you see):

All 3 selected items (hidden and regular):

Btw I never unplug the drive because I don't need it, I use it only for ReadyBoost and I don't care how much space there is left while ReadyBoost does it's job, I am just interested in the problem or should I say "paradox"...

Edit1
After I set different cache size for ReadyBoost and it starts to do it's work, Windows reports 3.80GB free while ReadyBoost works in background applying the cache, and after ReadBoost finishes the applying process, Windows shows the wrong free space size again...

Edit2
After formatting flash drive and re-enabling the ReadyBoost everything is back to normal. So the question is closed and solved (but don't know what was the problem anyways)...

Solution 1:

I had the same problem with my 16 GB flash drive. It turn out my flash drive was storing some files in .trashes. You should go the command line and navigate to your drive. Then use the command "dir" to view everything on that drive. You can then remove files manually using "del".

If you prefer to not use the command line, then try UtahJarHead's program.

Solution 2:

Download WinDirStat and find your files. It's open source and free. http://windirstat.info/ It will list all of your files in a nice graphical display with sizes so you can see exactly what's taking up your space.

After reading your below comments, your drive is screwed. There's an issue with flash that crops up rarely. Files will be deleted, as in NOT SHOWING, but the space will still be allocated by the drive. If this is the case, the only thing I've ever seen is that it is permanent damage.

Copy your data off, format it, and hope you get the full size returned to you.