If you've been using the 30-day trial version of Microsoft Office 2010, here's a nice tip for you: the testing period can be extended for up to six months. Much like Windows, the popular productivity suite contains a so called rearm function that gives you 30 extra days to activate the program. The command can be used up to five times, and if used at the end of each 30-day grace period, you can run Office 2010 for up to 180 days without entering an activation key.
The procedure is rather simple, too -- just open a command prompt window as administrator and run a file named "ospprearm.exe" which should be located in %installdir%\%Program Files%\Common Files\Microsoft Shared\OfficeSoftwareProtectionPlatform, where %installdir% is "C:" on most machines and %Program Files% will be the Program Files (x86) folder If you installed the 32-bit edition of Office 2010 on a 64-bit operating system.
As an alternative to the above steps, there's also a free utility available here to extend your trial period with the click of a button. The rearm feature is aimed at enterprise administrators who use a single copy or image, to deploy a supported operating system and accompanying software on hundreds or thousands of PCs. Nevertheless, the "trick" has been widely publicized online to regular home users and Microsoft seems okay with it.