A file sharing program called WinMX (winmx.com) does something to XP when it is installed. What ever user the program is installed on is the only one that Windows Explorer will work in. You cannot open My Documents or My Computer or anthing else that uses Windows Explorer under any other user. It also effects the uses or Internet Explorer in some instances. I discovered it last night when I uninstalled WinMX because they keep updating version so often and you cannot connect with an old one. I was tired of udating the program. After I unistalled the program Windows Explorer started working again under all users.