how can i format my usb

If you have not been using 'Safely Remove Method' (accessing the system tray icon and shutting the USB stick down BEFORE removal) and you've just pulled the USB stick out of the socket - you have ended up corrupting the partition inside the stick.

If you cannot format the stick completely, you may well have destroyed the data structure within the stick and it is now in Silicon Heaven.

Try formatting it in a different USB socket or in a different PC. If all this fails - your stick had died (probably due to unsafe removal).

It may not be an actual 16 GIG Capacity. Many of the cheaper Big Thumb Drives use compression to get their stated capacity and if that is the case you'll need to use the Thumb Drive Makers Utility to rebuild the drive.

If it was a Native 16 GIG Capacity you wouldn't have any problems formatting the unit on any computer but none the less to maintain compatibility you should format it to a FAT 32 Partition/s not NTFS.

Col