If you have a pen-drive and wondering that its usual capacity is showing less as what it should to be. then may be you require to repair it using a good pen drive utility.Few days back i was also caught in the same situation as one of my 4GB capacity pen-drive suddenly started misbehaving as every time i try to format it using the normal windows format option its storage space decreases. And in no way i was able to locate the problem.
Then I decided to use why don’t use any pen-drive format utility and after a hunting for such a application (though I have founds tons) I sticked to the HP Format disk Utility the best to format any pen-drive if it is repairable.
If you are also having problems with your pen drives then why not give this a try.