1) Windows (and some programs) like to be on the C: Windows is so fanatical on the point that it will kindly rename the partition for you if you assign it a different drive letter.
2) Be careful when setting something up that is not standard. Some things simply will not work, others will work with protest, and there is always the issue of confusing your drives, or running out of partition space, only to re-size the partitions, corrupt the disc in the process, and loose everything that is not backed up elsewhere (yes, I speak from experience... thankfully I back up like a maniac)
3) You can try to resize, rename, and manage your partitions via a program such as diskpart (my personal favorite), or partition master (if you get easily frightened by dos prompts). But as a general rule of thumb I would start over from scratch unless there is something on the parition that cannot easily be recreated.
Lastly; Stay away from unnecessary portioning of a drive. It gets messy quickly, and most of the time if you NEED to put stuff on a seperate partition (backups or other reasons), then really the data ought to be on a seperate physical drive in the first place.
For an example here is my setup:
c: SSD for Windows, programs, small files (documents, music, etc), and Adobe cache files
d: HDD for bulk files, and files not often accessed such as video, pictures, old projects, etc (this drive is normally asleep)
e: 2 HDDs in RAID1, this has the backup of my computer, my laptop, and my wife's computer. It also houses copies of the finished products of various projects that I want to keep, and also is used as my video drive when I am doing big video edits that will not fit on the SSD
Each drive has a use and a purpose, everything has a local backup (as well as DVD backup for important stuffs, and external HDD backup of everything), and the HDDs tend to stay in sleep mode most of the time (unless in use) to prolong their life.
Anywho, just food for thought. Hope it helps