Lenovo includes Office 2007 on all the computers they sell. By default, Office 2007 behaves as a trial edition good for 30 days.

For those who have purchased an Office license from Lenovo, there should be a Certificate of Authenticity and a Product Key in the box. I have not personally tried the following procedures, but you should be able to launch the Microsoft Office Activation Assistant and enter your Product Key there. The Activation Assitant will reconfigure Office based on the the edition of Office the Product Key is for and remove the components not applicable to your edition of Office. Additionally, it will activate Office, thus converting the trial edition into a full edition and remove the 30 day usage limit.

Do create a set of recovery media at the earliest opportunity. If something goes wrong with your computer's hard disk, this is the way to restore the pre-loaded software.