How can I recover a broken Windows admin account on a machine that runs both Win7 and Ubuntu 10.10?

I'm using a Compaq 610 laptop running Ubuntu 10.10 and Windows 7. I left a Windows 7 administrator account logged in in the morning, but when I try to log on now, I get the error message

The user profile services failed the logon. User profile cannot be loaded

and I can't access the admin account. Is there a way to get into my account? How can I start Windows 7 in safe mode when Ubuntu is one of the operating systems?

I've logged on with Ubuntu and discovered that the AppData folder in the directory C:\Users\Sam Samson has been deleted.

What can I do?