Are you sure?
As far as I know, one Windows may be installed on the single machine only. So when you reinstall it to another machine, you need to activate it one more time. I'm not sure exactly how Windows defines if it works on a new hardware but the key information is motherboard (or CPU). Other words, if you change your video card for ex., Windows will just notice it and ask for a new driver - it will think that it's the same machine. But when you change your mobo (and maybe a CPU), it defines this comp as a new machine and will require the activation.
The same situation is with drive imaging.
The other problem is related to drivers. If the imaging software isn't smart enough and haven't the exact feature that allows to restore the image to different hardware, it won't work and will have a loooot of troubles.
I almost sure that Ghost doesn't have such kind of feature. It includes in Acronis True Image Workstation (called Universal restore) or in Symantec's Livestate Recovery for example... But it isn't presented in Ghost.
To confirm my words: I've already used True Image to restore to another machine and can say that all worked ok and all drivers and different hardware were detected correctly. But Windows did require activation after the image restoration. And it definitely requires a special feature to perform this task.