Cannot set default, access denied

After a recent Windows 7 (Ultimate) update, I cannot print. When I try I get the message that I must set a default printer. My printer has disappeared from 'Devices and Printers'. If I am printing at a time when the print dialog box appears, I can find my printer in the drop down and choose it and print. I have been told 'access denied'. I have tried 1. reinstalling my printer several times, including updating drivers 2. System Restore 3. Read instructions on how to fix the registry - but I am not savvy enough to understand this. 4. Right click my computer, computer manager, local uses and groups, and I enable every one. What is next to try?