Microsoft Word is licensed software - there was an option from Microsoft to try it for 30 days at no charge before buying but I can't find reference to that now.
There's a great Home and Student version of the Office Suite available for less that £70 [that covers 3 PCs] from places like Amazon. The package is well worth buying even for one PC, even if you ignore Excel and PowerPoint, which are included.
Yes, it is £70, and why don't they sell a single copy for £25 or something, but the fact is, they don't.
If you need it for the course, then I would suggest you buy the Office Suite as above.
If there is a free download of the software, and it doesn't come from Microsoft, it won't be safe at a number of levels.
Word 2007 is great software. Word 2010 is due soon and people buying the 2007 version now will be likely to get a free upgrade when it is launched.