When you click on the first partition (23.41GB) not Disk 1 at the left can you right click and assign a letter?
Edit: I think I see the problem. The first partition of disk1 is marked active.
open a cmd prompt. Type cmd in the search box and right click "Run as Administrator"
List disk ( you should see your Disk 0 and Disk 1)
Select disk 1
list partition (look for the partition number of the 23.41GB partition)
select partition # (# being what was listed in previous step)
Detail partition ( you should see details of the partition and it being marked active)
Now try and give the partition a drive letter by selecting the partition and right clicking.
Edited by JohnC_21, 04 May 2014 - 09:04 AM.