Methods and arrangements are disclosed for secure single sign on to an operating system using only a power-on password. In many embodiments modified BIOS code prompts for, receives and verifies the power-on password. The power-on password is hashed and stored in a Platform Configuration Register of the Trusted Platform Module. In a setup mode, the trusted platform module encrypts the operating system password using the hashed power-on password. In a logon mode, the trusted platform module decrypts the operating system password using the hashed power-on password.