Click start control panel administration tools computer management disk management right click on your drive select properties click tools you should see click check now click start two boxes

automatically fix files and scan for and attempt recovery of bad sectors place then a tick in one box then select check now start or you might tick one box then return after its finished the first
then return and tick the second box
you should not do anything while the chkdsk utility is in progress any input may damage this drive

click start click on computer then right click on your usb drive select format
hope this helps you