Resize OS partition but keep factory reset option

Hi,

I have Dell latitude 3540 with Windows 7 Pro. The system is with 0.5TB HDD, but with only one user partition. I would like to resize (shrink) the existing user partition (drive C) and to create an additional user partition (e.g. drive D). I would store all my data (documents, photos, movies) in drive D and the C would be for OS exclusively.

Question is: Will a factory reset still work with a resized partition? After performing factory reset, will all data remain on drive D?
 What is the best way to do that to ensure that factory reset works flawlessly?

Thank you,
Jonas