Remove original drive in dual boot system and replace Win 10 SSD? How?

Here's the situation. I have a 17" Sager laptop with two hard drives set up with dual boot. The first drive is the OEM drive that came in the laptop and Win7. After I installed my work software, and made sure the machine was stable, I used the computer in this configuration for a few months. I then decided to set up dual boot using a Crucial SSD drive with Win7 in the vacant 2nd hard drive bay. This allowed me to work from the old drive while I organized the SSD with my work software. (AutoCad, Rhino, etc) and made sure it was stable. After the SSD setup, it became my primary drive, and I never used the OEM drive again.

Now, with Win 10 about to be released, I was thinking about removing the idle l OEM drive and adding a new SSD and Win 10. (This would let me keep working from the Win7 SSD) However, If I remember correctly, the dual boot information (Boot Manager?) is on the original drive. Wouldn't removing that drive also disable the current Win 7 SSD?

It has been about 3 years since I dug into a computer and much has changed. I'm hoping someone here can give me info, suggestions, or even a step by step procedure to get this right.

thanks in advance.

Please post back a screenshot of Disk Management - Post a Screen Capture Image
with all drives connected.

Ok. So WIN 10 is out and I have created a boot disk using MS creation tool and I have a new SSD for the OS. I'm hoping someone here can tell me the procedure to replace the old OEM HD with the SSD + Win 10 and keep the dual boot with my old SSD with Win 7. I'm assuming once I figure out the procedure, I can install Win 10 on the new SSD and it will ask for my Win 7 serial number and that will make everything good to go?

Here is the disk management partition image as suggested.