Try the evaluation version & it will work fine for 60 days.
I think 60 days are more than enough to prepare for your exam.
Microsoft Office Enterprise 2007
Office Enterprise 2007 includes:
Office Word 2007, Office Excel 2007, Office PowerPoint 2007, Office Outlook 2007, Office Publisher 2007, Office Access 2007, Office InfoPath 2007, Office Groove 2007, Office OneNote 2007, Office Communicator 2007, Integrated Enterprise Content Management, Integrated Electronic Forms, and Advanced Information Rights Management and Policy Capabilities
You will need a working hotmail email address to download this.