One Drive Two Situations

Hello
The computer has a C drive and a D drive both with almost the same folders and files.
I want to delete/format D drive however it is the Program Files and Program Files (x86) and the Windows 7 OS.

On D drive Program Files (x86) is missing.

On Start all the application’s ‘properties’ reference c:\program files(x86) thus my conclusion C drive is the drive I need to keep.

What I found in any application I open - if I have to do a save as that save is directed to D:\Libraries. In fact all the saves are in D:\Libraries; the C:\Libraries are mostly unpopulated. What I did in preparation to format D drive was move all the assets from documents/photos/videos/audios from D libraries to C libraries.
I write this because of my uncertainty – I am interested in saving all the data from D and then formatting D knowing that C is healthy with a working OS and Programs Files.
Let me know if I am safe to format D. Here are two images showing information on C and D drives.

To test boot I used EasyBCD / Drive C booted fine; Drive D attempted to launch Windows 7 ; and simply reboot taking me to the boot menu.

Let me know if I can remove D drive / I only need one clean system and one clean boot.
Thanks!