Sometimes, when you plug a USB stick and delete them again, it will not respond well to commands you give in your system. You may get an error eject usb drive sepertiwrite protected - can not remove the usb drive. Here a nice tool that allows you to amanSafety Remove the USB drive from a PC with USB Disk Ejector.
USB Disk Ejector is a simple tool that allows you to remove your usb drive safely from your computer without much effort and you can avoid some errors that do not want USB Disk Ejector support all USB devices.
Direct Download and extract your run more powerful program requires no installation and it will automatically recognize all devices connected, double click to disable the USB one that you want to Safety Remove USB drive from a PC.
http://quick.mixnmojo.com/downloads?download=USBDiskEjector1.1.2.zip