[daniel1212]

You mean the drive letters you want are not being used, but are not available?:

[Paul R.]

Right. As in your example, E, and F don’t show up, but in your case I assume they are in use, just like “B” (floppy?), “C” of course is the boot drive, and I assume “D” is the DVD.

In my case, “F” became “G” (the 500 GB MX500 SATA drive), and “E” (the original C: drive before the 1st cloning) is in a different machine entirely now.