M$ says that you need to do a clean install to go from XP to 7 --
and the article says it ain't pretty.
http://apple20.blogs.fortune.cnn.com/2009/02/25/windows-7-trouble-on-the-upgrade-path/
and the article says it ain't pretty.
http://apple20.blogs.fortune.cnn.com/2009/02/25/windows-7-trouble-on-the-upgrade-path/