Do this:
Be sure you are connected to the internet
#1 -click start
#2 -mouse over “All Programs”
#3 -Click on “Windows Update” or “Microsoft Update”
#4 -Click “Custom” and it will check for updates
#5 -When finished click on “Software Optional” on the left side of the page
#6 -Check the box to any and all of the updates marked for Media Center Edition 2005, one of these includes a keyboard compatibility update