Hmm ok how about if I plug the Ssd into the old computer thru a removable usb enclosure (which the Ssd came with) and somehow tried to install Windows 10 on that (can you do that on a computer running Windows 7) and then took out the old computer's hd and installed the Ssd? Possible, but fraught with problems unless the two PCs are very similar.
Chances of it working flawlessly when moved to a 2nd PC are slim. Anytime you install an operating system on a drive in a PC, the windows installation will set itself up based on the motherboard devices, chipset, CPU, etc.
