Off 

Off 

Off 

No power or the key switch is in the Off position.  

Off 

On 

Off 

Failure mode. System has electrical power.  

Off 

Off 

On 

Failure mode. System has electrical power.  

Off 

On 

On 

Failure mode. System has electrical power.  

On 

Off 

Off 

System is hung, either in POST/OBP or in the operating system.  

On 

Off 

On 

Hung in OS. 

On 

On 

Off 

(Hung in POST/OBP) or (hung in OS and failed component in system). 

On 

On 

On 

(Hung in POST/OBP) or (hung in OS and failed component in system). 

On 

Off 

Flashing 

OS running. System is operating normally.  

On 

On 

Flashing 

OS running and failed component in system.  

On 

Flashing 

Off 

Slow flash = POST. Fast flash = OBP.  

On 

Flashing 

On 

OS or OBP error.