Not to be picky, but the older version of Office is actually the problem. The version of Windows doesn't matter.
You have two choices - assuming you're logging into the network, you can run the application explorer and under drew > install software look for the Microsoft Office folder. There ought to be an icon for the updated file filters (file compatibility update), or there's another icon for the Office 2007 install. The former will allow you to open docx files, but you can't use all the new features, the latter will give you the new version of Microsoft Office, which takes a little getting used to.
You can also ask the people sending you documents to use "save as" instead and pick the Office XP/Office 2003 compatible Word format when they're saving stuff to send to you. It's easy to do.