you can just plug it in, its best 2 do a format, it might work! just try it!
As long as you have an install disk you could try a Windows repair, it keeps your existing files but re-installs the components needed to get it running (in the case of changing motherboard chipset or processor).
You cant use a os that was installed on a differnt system.
And if it does work you will have loads of problems.
You need to install an operating system on the system your gonna use it on.
if im right that is what you were asking.
So you need to get an installation CD and run that.