I helped a lady upgrade from XP Home to XP Pro and all of her programs worked afterwards, and that included Microsoft Office XP Professional.It said to go to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Windows Update\AU. I think you need to install the Windows Update Agent. The problem is my registry doesn't have a (Windows Update\AU) How can I fix that. williamp, i am using windows xpsp3 and i don't have the regkey that you mentioned on my computer.. go into windows "services" and make sure that the "automatic updates" service and the "background intelligent transfer service" are enabled.. Using Free imgburn However that is not the end of the issue. What if I partition my large HD into two partitions; one with my remaining XP home and then install the XP Pro on the other.Since SP-3 was released, there have been may be 400 updates or so. Is that possible morcomp, You could do that BUT honestly would be more work than it's worth in my opinion. I think you are correct with your comment about XP.I would, however very strongly recommend that you buy Acronis True Image Home Edition backup program at and make a backup of your system as it is now, and create a bootable recovery media disk, so if it doesn't work for you, or if for any reason, you decide that you would rather go back to the Home Edition, then it would only take about an hour to run that backup to get it back.