Organising partitions/Transfer files from (C:) to (D:)/etc.?

When I bought my laptop, its 160GB HDD came separated in two partitions (is that the correct terminology?) = C:\ drive and D:\ drive.

I left it that way, and so far have only used C:\ because 1) I have no experience in using more than one drive, 2) that's where most programs download to anyway, 3) it contains the My Documents folder where I organise all my personal files into My Pictures, My Music, My Videos, etc. folders., and 4) I had not yet run out of space.
Now, despite deleting what I could and buying an external HDD on which to archive and back things up, my C:\ has used up 65.3GB out of 71.9GB of storage. Meanwhile D:\ has 71.6GB out of 72GB available (free). However, my D:\ drive is completely emtpy - no hidden files, temps, NOTHING - so where did my 408MB go? ...

I've read up on partitions a little and believe that that's how my laptop's memory is organised. I'd like to ask ...


* is my assumption correct? and if not, what is the explanation for the memory being split into C:\ and D:\?
* which files are best (or at least safe) to move from my C:\ to my D:\ drive?
* how do I go about safely moving them?
* will everything continue running smoothly after I move these files? or do I need to point programs, applications, etc. to the new location of the files?
* is there anything else I should worry about (or at least take into consideration) before/when doing this?
* there seems to be a lot of talk about the benefits of organising your files in partitions. how can I optimise my use of the C:\ and D:\ drives?
* lastly, I noticed that my C:\ drive runs on FAT32 and my D:\ runs on NTFS. Why is this? And does it affect what I intend to do to either of them?

As you can see, I'm a total partition-newbie. So thanks in advance to anyone who's read this ^ and posted that v Very Happy .