USB Drives size reduced

[shine8mile]

I have an 8GB mp4 player....It can store files and all. It had a lotta junk so I often format it. But one day when I formatted it. The size of it just reduced to 957mb. Tried to format it using HP's USB format tool. But still its the same. Is my USB drive corrupted or is there any way that I can bring it down to work again.
Please help me and thanks in advance for help...!!!