I'm using Microsoft office home and student trial version and it was now expired.. I want to uninstall it.. but whenever I run the uninstaller there's an error saying

"set up cannot continue because the required file is either corrupted or not available. run set up again from the original source disc or download location"

I tried running the installer but the error still pops up.. I also try using the ccleaner to uninstall it but it doesn't work.. please help.. thanks!

Missing the actual version of office (Office 97, Office 2000, Office 2003, Office 2007), try this page and see if the uninstall steps work for you:

What should I do if I can't remove or reinstall Microsoft Office? - Knowledge Base

Also, Microsoft has a utility that may do the trick as well:
Description of the Windows Installer CleanUp Utility