I've been having this particular problem for a while. This is my mom's old computer and she used to have NetClient (or at least I think it was) installed on it. Quite a long time ago, I uninstalled it when trying to change how users logged in and out of the computer, as it told me that this program specifically was blocking the Welcome Screen and Fast User Switching from being enabled. Now that is has been removed, I have been getting a different error message, while these two options are still blocked. The message is as follows:
"A recently installed program has disabled the Welcome Screen and Fast User Switching. To restore these features, you must uninstall the program. The following file name might help you identify the program that made the change: msgina.dll."
This is a Dell Latitude D620 laptop, running Windows XP. Any advice?