When you buy an OEM copy of Windows 7 you get one licence. Once you install Windows 7 and activate it, that licence is tied to that machine, you cannot use it again. You can install Windows 7 on the laptop, but you won't be able to activate it using the same product key that you have used on the desktop machine. You can use Windows 7 for 30-days before you are required to enter a product key. You'll need to purchase another Product key, which can be done online in a matter of minutes. Just install Windows 7 using the disc you used on your desktop (Without entering a product key) and once finished, go to activate windows, when it asks you how you want to enter a product key, select buy a product key online.
