You are correct Sheila, you can install word from another ther disc, but the problem is that technicaly your user licence from microsoft is for a single user nad so of course they will not want oyu to use the disc from your desktop on to your laptop.
As i say you could install the disc but be aware of copyright infringement. you would only need to spend £350 on the complete office package. if you wanted the latest version of word you could download a trial of office proffesional (Beta) this has not been released for sale but microsoft are looking for people who are prepared to try it for a limited time for free ( until the end of January i think) and give there opinion.
if this is not what you want then buy a copy of word from somewhere like pc world or somewhere reputable for about £70. if you are a student you could always obtain a copy of the student office edition for about £100, the advantage of this is that it will give you other packages as well as word such as excel and publisher.
I hope this helps kind regards