Q. What are the differences between Windows XP Professional and Home Edition versions?
A. The official Microsoft comparison is at http://www.microsoft.com/windowsxp/home/howtobuy/choosing2.asp.
In some respects the Home Edition has fewer capabilities than Windows 98/Me and one must upgrade to the Pro version (and pay noticeably more) to get them. They include:
Login into a Windows domain server (Windows NT, 2000 Server) on a local area network.
Personal Web Server. The Pro version has Microsoft's Internet Information Server which has a much more sophisticated web server than the Personal Web Server plus ftp and gopher servers. The IIS web server can run on the Internet.
I have heard from other sources that the Windows XP upgrade cannot be used to upgrade Windows 95. When I clean-installed the Home Edition upgrade on a bare hard disk drive and it asked that a CD from a qualifying product be inserted in the CD-ROM drive for verification, Windows 95 was listed as one of the qualifying upgrade products. However, I have not actually done it yet with a Windows 95 CD.