You're limited to 6 reinstalls. That includes the moving of the os to another machine. Point is if you make a habit out of it and M$ sees the hash numbers with the key code coming in too close together they lock you out. You wind up having to call a tech. Be honest about what you did dishdog. I moved one of my xp home os's from my retired p3 to my toy p2 and it called in no problem. But the p3 had been sitting in the cupboard for 90 days. Point is be honest with them. You'll get a lot farther if you do.