"User profile cannot be loaded" message after automatic update

Last night my laptop started doing an automatic Windows 7 update. This morning I cannot log on -- when I type in my password, I get an error message that says "The User Profile Service service failed the logon. User profile cannot be loaded." Any ideas?

Thank you. This did work. The only problem is that none of my document files are visible any longer. I can find them using "find" and searching by name but I can't see the folder where they are located. Maybe this is a necessary outcome of the fix that involved changing the user profile, and if so it's worth it, just wanted to check if there was some way to retrieve visibility of my files. Thanks again.