If you have a USB Drive that is not recognized by Windows the problem is usually that you have too many network drives or other drives that occupy all the drive letters D: E: or F: which is the normal drive letter of a usb drive. The way to correct this problem is to change the drive letter of one of the other devices. See the instructions below.
1. First connect your USB Drive to a USB port.
2. Now right click on My Computer Icon on the Desktop and select manage. You will get the computer management screen below. Select on the right window Disk Management.
3. Now you will see the disk management screen below. To change a drive letter select the CD-ROM 0 drive and right click on it and select change drive letter and path.
4. The Change Drive letter and path window will open, click on change button. To get the change drive letter or path window, see below.
5. Now if you click on the drop down window on the right where the D: is you can change it to say R:. Clicking on ok will change the drive letter. You should change the CD drives to Q: and R: they are not usually used as network drives . Close all of the windows out. Reinserting your USB Drive should enable it to be recognixed as D: or E:.
The attached word file is the same thing you just read but with photos to help.