There is a version of Open Office that one can run off a pendrive.
Back in the day when I was still running a Windows-based PC I had most of my software on a thumb drive, including the above mentioned office freebie, ftp, browser, even a virus scanner.
If you still use Windows and want to run as much stuff off of a usb drive as possible then portableapps.com is a good place to find what you're looking for.
Personally I'd recommend switching to a Mac, after the initial month of pain comes a feeling of satisfaction and the "glad I did it" approach. There's no going back once you make the hop.
