USB Flash drive recovery

I have a USB Flash drive that reads used space 0 bytes and free space 0 bytes. I learn that this may be caused by a bug in Windows XP. I have saved similar drives from the above situation by using a format utility however the resulting drives appear smaller than they actually suppossed to be. Can anyone explain this phenomenon and give my the name of any utility that may help me recover the drives on an XP platform since learnt of similar feats through linux and Mac platforms ? Thanks