How can I get back Microsoft Office 2003 after downloading a trial of Office 2007?

Here’s the story: A school-owned computer has (had) Microsoft Office 2003. Recently, a student wanted to view a template that he/she found on the Office web site. It said that he/she needed to download Word 2007, so he/she did. Now, the trial period of 30 days has expired and the new software is useless. Also, for some reason or another, Word 2003 cannot be accessed.

The computer is running Windows XP Professional SP3, the folders Office11 and Office12 are both still existent in the Microsoft Office directory, and the original Office 2003 CD could not be found. Is there any way to get back 2003 at this point in time, or would I have to go retrieve a CD to get back Word 2003?