Ubuntu via Wubi is suppose to be just like another program you can remove in the
usual way as other Windows programs, or is my memory off today? Hopefully, you
already copied to USB what was important and any bookmarks were saved via
Xmarks, etc.

Recovering from Wubi install=Google search string:
www.google.com/search+from+Wubi+ins\
tall&ie=utf-8&oe=utf-8

https://wiki.ubuntu.com/WubiGuide

http://linux.about.com/od/dist/gr/dstwubi.htm

http://neosmart.net/forums/showthread.php?t=5004
kubuntuforums.net/forums/index.php?topic=3113011.0