Try reformatting the flash drive. Copy all your important files somewhere, since reformatting the device would erase all saved data. Go to "My Computer", right click on the usb device, click "Format...", click "Start" on the window that pops-up, click "ok" and wait for the formatting to finish. This should erase all data on the device, including hidden files that might be taking the space up.
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Try reformatting the flash drive. Copy all your important files somewhere, since reformatting the device would erase all saved data. Go to "My Computer", right click on the usb device, click "Format...", click "Start" on the window that pops-up, click "ok" and wait for the formatting to finish. This should erase all data on the device, including hidden files that might be taking the space up.