Locked out of my Dell Inspiron Mini-Duo Laptop

I have not used my Dell Inspiron Mini Duo lap top in many months and now it will not let me sign in. 

As far as I recall, I never set an access password as I am the only one who uses a computer. The message says:  The user profile Service service failed the logon.  User profile can not be loaded. 

Any ideas how to break in to my own computer?