Portable software runs on your USB key drive or your iPod, or a memory stick, or any type of external drive you plug into a USB port. You don't have to install anything on the computer's hard drive. It's like carrying your office around with you. Or... carrying your home to the office. These kind of apps are becoming more and more popular as USB flash drives get cheaper and cheaper. If you ever do any work at more than one computer, go get one now, then install this freeware. Then you can do something else. If you want. Or, you can just hold your key drive and feel good about what you've just done .....(free).....