I work for a laptop company and very often our products come with a free trial of MS Works which asks for the product key when you first turn on the computer (to activate the free trial).
Sometimes it's not obvious that it is MS Works asking for the key and we get a lot of customers calling and saying the same thing; they put in the key on the base of the machine and it doesn't work.
I may be wrong, but try this:
(presuming you use Windows Vista here, btw)...
Go into your start menu, in the search bar at the bottom, type "activation". Hopefully something will come up at the top of the start menu that says something like "Microsoft Activation Assistant".
Click on that, should say something like "generate trial key" or something similar. Click on that, copy the key it gives you and put it into the activation box.
As I say, assuming a lot about your machine here, as not seeing the thing myself I couldn't tell, but this might be worth trying just in case the manufacturer has included this kind of free trial thing.
