Can I boot by my old hard drive?

[Skylineyt]

I have a ssd which I want to get windows 10 on but I also have a 3tb hard drive with also windows 10. Can I boot from my older hard drive, will that boot? I have loads of stuff stored on that HDD. I do have a 16GB memory stick with win 10 boot on it so I can boot from that but then I'll have 2 copy of windows 10.

 

[USAFRet]

I have a ssd which I want to get windows 10 on but I also have a 3tb hard drive with also windows 10. Can I boot from my older hard drive, will that boot? I have loads of stuff stored on that HDD. I do have a 16GB memory stick with win 10 boot on it so I can boot from that but then I'll have 2 copy of windows 10.

Unsure of what you are asking.

Was the OS on the 3TB installed when that drive was in this current system?
Do you wish to use the OS, or do you just want some of the data off it?
Does the system boot properly from the SSD?
What does the USB stick have to do with this?


EDIT:
Correcting myself.
The SSD is blank, and you want the OS on it?

 

[USAFRet]

Pretty much I have my original OS on my 3tb but I have a ssd. I was wondering if you can boot straight from my current hard drive.

Iv just built my pc, I have windows 10 on my memory stick to boot if I can't boot from my 3tb drive. Should I boot from my memory stick and install windows 10 on my ssd?

The OS on the 3TB is from an earlier system?
And now you have built a whole new one?

2 considerations here, Operation and Licensing

Operation - It is highly advisable to do a clean install of the OS on the new SSD in the new system

Licensing - To transfer that OS license from the old system to this new one, you have to link the OS digital entitlement to a Microsoft account.
Read and do this:
https://support.microsoft.com/en-us/help/20530/windows-10-reactivating-after-hardware-change
http://www.tomshardware.com/forum/id-3164428/windows-build-1607-activation.html