If the only difference is the 4/8Gb of RAM, that shouldn't cause any major problems. It's true that (since XP I think) waking up an hdd in a different computer will cause Windows to question its own legality, but it starts up perfectly and then asks you if you've altered something and, if not entirely happy with your answer may ask you to call them. I've had to do that a few times and MS have always happily given me a new code to type in.
So going back to your problem, have you tried running it back in the original machine, and is it working OK in that?
Last edited by boguing; 28th April 2018 at 22:11.
Reason: left the 8 out