Thats a first for me. Let me ask you this. Does your user have admin rights to their profile on the computer. If not grant them the administrator rights. log off and log back on. Set the default printer and then restart. If it takes it then set the user back to what ever you had at before.
If that fails then Click on Start, Settings, Printers, File, Server Properties, and delete the drivers of the printers that you do not need.
If that fails then try re-installing the printer driver. Let me know how it goes.