<human>: Can you summarize the given text in a few sentences?

I have 2 laptop hard drives from an old destroyed laptop. The laptop I currently have has only 1 place for a hard drive. I also have a portable hard drive. 

The 2 laptop hard drives (I'll call them A and B for ease of understanding) have pictures, movies, and music on them that I want to transfer to the portable drive. Drive A has the OS and the pictures on it, so that's no problem. I can just plug it in and transfer over.

Drive B is the issue. I can't plug it into the laptop, because then the laptop will be left without an OS. I have no other way to connect it, and I want to access my music and movies.

Is there an easy way to have a (very simple if need be) OS on my portable drive, boot the laptop from that, with drive B installed, and transfer everything over?
<bot>: 4 hard drives, 2 with os, 1 portable usb and 1 hard drive slot. Need to transfer info from hd without os to portable, but with no os I can't do it!