Windows maps disk letter to concrete disk and stores this information in registry under HKLM\System\MountedDevices
. So if you've earlier connected your new disk as non-system, it already has letter F:
assigned.
If it allows you to run Regedit.exe
as Administrator, then simply delete value \DosDevices\C:
and then rename \DosDevices\F:
to it and restart.
You may also do this offline from another system by editing system registry hive from %drive%:\windows\system32\config\SYSTEM
, where %drive% is your new disk connected to another computer.
You may also use Windows Recovery media and using regedit.exe
thatway.
Alternatively you may use some live linux distro containing reged
utility, eg. pogostick.net, System Rescue CD
More about editing registry offline Search here on SuperUser.com