A system and method for monitoring a computer, particularly a pay-per-use computer, uses an isolated computing environment or supervisor. The isolated computing environment boots prior to any boot device associated with an operating system, runs concurrently with the operating system and monitors and measures the computer in operation. Once the isolated computing environment determines the computer is not in compliance with the required policies, the isolated computing environment may either impose an impediment to use such as slowing clock speed or completely disable the operating system. The user may have to return the computer to a service provider to restore it from the offending condition and reset the computer to an operational state.