Portable Ubuntu for windows XP and Vista

portable-ubuntu Portable Ubuntu for Windows is an Ubuntu system running as a Windows application. This system is built with the Colinux Kernel, Xming X server and Pulseaudio server for Windows. The Portable Ubuntu can be directly run from the thumb drive, and it can be used as a standard Operating System with installing and using Ubuntu programs and manipulating files. The interface of portable Ubuntu is a standard orange GNOME based and it can be downloaded and distributed freely.

You can download Portable Ubuntu for Windows from here and here the file size is 438MB, so the download can take a while.

To install and use portable ubuntu for Windows XP are:

Double-click the downloaded file and select a location that the archive should be extracted to, then uncompress the archive by clicking extrac button.
After the archive has been uncompressed, you should find a folder called Portable Ubuntu, go to the folder.
To start Portable Ubuntu, right-click bat file named run_portable_ubuntu.bat and select open (If you are using the Windows firewall, you might have to unblock two or three applications that are needed to run portable Ubuntu). Afterwards, you should see Portable Ubuntu start up.

For complete tutorial about install portable ubuntu in windows xp and vista can be downloaded from following link (how to):