Windows 10 help needed

[XFalsePr3acherX]

So I put a hard drive in a second computer that was formatted and I put windows 10 on it and signed in with my Microsoft account. But when I went back to my main computer I booted it up and went right to the windows install screen, I don't know what happened between when I was setting up my second computer until then when I had the OS on my SSD that was in the computer the entire time and it just disregarded that boot file on it. So now when I look at my storage for my SSD it says "Other People" but that other people is my own account, is there any way I can get my stuff back and avoiding this in the future? 

[WhitetailAni]

You can't put 1 license key on 2 PCs.