I guess that by "stationnumber" you mean what I call the drive letter.
Log onto Windows with an administrator account. Go into Control Panel|Administrative Tools|Computer Management|Storage|Disk Management. Right click on the current D: which is supposed to be F:. Go to "Change Drive Letter and Paths". Change D: to some unused drive letter, maybe Q: (I don't remember if you have to log off or reboot to make this take effect. If you do, the machine will no doubt tell you.)
Now the letter D is free. Go to the current F: which is supposed to be D:, right click as above, and change it to D:.
After you have done that, go to the current Q:, which was D: a few minutes ago and is supposed to be F:, and right click and change to F:, as above.
You should be finished.