Fixed drive letter designations after Dual Boot install

Hi, I've installed W10 in my laptop in a dual boot configuration with W7 successfully. I used this tutorial https://www.tenforums.com/tutorials/2...ndows-8-a.html I'm setting up to do the same thing in my desktop and have a couple questions about drive letter designation after doing it. I created a 30G partition on the C drive of my desktop for the W10 install.

My laptop has one drive, the OS "C" drive, I created a another partition for W10, after installing W10 using the USB ISO "boot from USB" instruction when I'm in W10 it shows as the C drive, and the W7 partition is inactive D drive. Just the opposite when I'm in W7, it shows as the active C partition and W10 is the inactive D partition.

On my desktop I have the 120G C drive for W7, a 500G D drive for backups, a fixed CD-ROM E drive, and a virtual CD-ROM F drive. I've made a 30G partition on the C drive to install W10 on for the dual boot. The question is when the auto backup runs (I have it backup & image every Sunday at 7:00pm) it backs up the C drive to the D drive. Will the W10 dual boot install change my backup drive letter to something other than D, or will the non OS physical drives keep the same drive letter? I will have to remember to be in W7 for it to be the C drive when it backs up, but my concern was if the dual boot was going to change my backup drive to something other than D. That would affect the backup.

I've attached disk mgmt. below, FYI the G drive is the USB with the W10 ISO

Attachment 21744

I installed W10 on the 30G partition I created on my C drive, while in W10 it shows as the C, W7 shows as D, backup drive shows as F.

Booted into W7, C is W7, D is the backup drive, F is the W10 install, so my question was answered.

Summary: While booted into W7 the C and D drives are the same as they were before W10 dual boot install. While booted into W10, W10 becomes the C drive, W7 is D and the backup is F. Fixed CD-ROM drive E didn't change, virtual CD-ROM is now G

Disk management below while booted into W7, F is W10.

Attachment 21783