First of all, if your copy of Office came with your laptop, then that copy is non-transferrable.
That aside, there is no way to deactivate Office ... but all is not lost. Assuming your copy is retail and not OEM, all you'll need to do is use the phone activation feature for Office. You'll call the activation center, say your activation code, it will cause an error, and you'll be transferred to an operator who will manually verify some details ("how many computers is this copy of Office installed on?") and provide you with the activation response code. If this is an OEM copy, you'll encounter considerably more resistance on the activation hotline, but you wouldn't want to do that anyway since it's illegal to transfer an OEM copy to another computer.
Keep in mind that the Microsoft EULA only allows for the transfer of a retail copy of Office to another computer owned by the same individual once per 90 days. You are only technically allowed to activate more frequently than that in the event of a hardware failure (I've never seen them enforce this though).
Also keep in mind that if this is a retail copy of Office 2007, you are legally allowed to install one copy on your desktop computer AND one copy on your laptop computer at the same time (one desktop and one portal device as long as they are both owned and used by the same individual). So you may not have to uninstall the other copy.