Windows won't remember drive letter assigned

I am running Windows 7 64 bit. I have a WD Passport USB external drive. One of my mapped network drives is labeled “G”. I want the external hard drive to be drive letter “F”. I can go through disk management utility and assign the drive with the letter “F” and it will maintain until I restart my computer. When I restart the computer, it reassigns the external drive to “G” and I have to repeat reassigning the drive letter. I have updated to the most recent driver. Does anyone have any suggestions?


By any chance, do you have another drive that already had this letter?


No, there are no other drives with that letter. My external has always been the “F” drive.