Several XP users have reported this problem with PDFs, but I haven't heard about it affecting Office documents. To associate the .pdf, .xls, and .doc extensions with the appropriate program, right-clicking the file and look for Open With on the menu. You might need to hold Shift when right-clicking. Some XP users have reported that although this fixes the file opening in the wrong program, the description in Windows Explorer is still wrong. I'm not sure there is any easy fix to that just yet. One user reported that making IE the default browser solved it, or reinstalling Firefox and NOT allowing Firefox to make itself the default browser.