Deactivate active partition

[Moffat Cafe]

I have an unconnected hard drive, call it drive A, with data on it that I would like to access. It has an active C: drive partition. If I temporarily connect this drive (in addition to my existing hard drive, call it drive B) to my PC I will have two active partitions which as I understand it, is a no no. Is there a simple way to make drive A's active partition inactive?

 

[Fardringle]

You can only have one active partition on each physical disk in the computer, but each physical disk can have its own active partition without any problems as long as the correct disk is set as the first boot option in the BIOS.

 

[Billb2]

I have 4 drives/5 partitions/3 OSs on this rig, three drives have active partitions.
Just plug it in. Windows will assign a drive letter.