TRUEfrancesca

My laptop came with a single SATA HDD that was partitioned into a C:\ and a D:\ drive.

I haven't used my D:\ until now that my C:\ has filled up. Once that happened, I dragged and dropped the 'My Documents' folder into the D:\ drive - then thought better of it, dragged it back into C:\ and came onto a forum for advice on how best to go about it.
Before all this action, the D:\ was always shown as having "Used Space: 0MB, Capacity: 72GB". After all the dragging-and-dropping to and from C:\, however, D:\ supposedly has "Used Space: 192MB, Capacity: 71.8GB".

I tried to return D:\ to its completely empty state by clearing it out, viewing and removing hidden files, using Disk Clean-up, running Defrag, etc. But it still shows as having "Used Space: 192MB, Capacity: 71.8GB"!

Why is this?
I mean, I know that amount of usable disk space is not always as advertised, but how come D:\ used to be able to to show 0MB used space, but now has to show 192MB used space even though it is just as empty as before?!

So now I'm thinking of reformatting D:\.
But since D:\ is just a partition within a drive, won't reformatting it affect my C:\ as well? If so, how?
Are there any (other) dangers to re-formatting the D:\ partition?
How do I even go about reformatting just the D:\ partition safely? (I really don't want to touch C:\ ...)

Finally, is there any other way that I can 're-claim' those 192MB?
(I know 192MB isn't much compared to the 71.8GB I've got left, but it's still a good 2 or 3 music-album's worth of space ...)

Thanks in advance! Any help is much appreciated!

Edit:
Bw, the defrag analysis offered the following info:

(things in bold are by me)

This just reiterates my question tho:
What and where are those 108 Total files and/or 13 Total folders?