Hard drive partition

[Black_1]

I have one hard drive in my pc and I split it on two partition C and D. Now I'm planning to install one more HDD and I don't want to reinstall my OS. Will this new HDD be one partition (third one) or do I have to reinstall os?

 

[USAFRet]

I have one hard drive in my pc and I split it on two partition C and D. Now I'm planning to install one more HDD and I don't want to reinstall my OS. Will this new HDD be one partition (third one) or do I have to reinstall os?

Just installing a new drive should not affect the current drive with the C & D partition. It will appear as E or F.
Unless you are looking to do something else.