apophis_91
Please clear up a point for us. Is this a properly bought and licensed version of the game, and you are having a problem moving it to a new PC (which means that it isn't on the old PC anymore), or a cracked copy? In the first case we can help you; in the second case we can't.
If all games are lagging on the new machine, that's a third issue. We'll ask for hardware specs and take a look.