Questions are always simple, it's the answers that can be tricky.
The answer to this one is a definite "maybe." Moving between an Intel and an AMD platform will almost certainly explode; other than that you may or may not have stability issues depending on how different the two systems are.
The newer the OS, the more robust it's going to be to this sort of change. However, you'll almost certainly have to re-activate Windows. If you're running an OEM preinstalled version, this may cause you headaches (and if you care, it will breach the terms of the licence agreement).
In any case, it's a good opportunity to start afresh. The risks outweigh the convenience IMHO, I'd always rebuild except in extenuating circumstances.