Troubleshooting Guide
2–8 www.hp.com Troubleshooting Guide
Troubleshooting Without Diagnostics
Computer powered off 
automatically and the 
Power LED flashes Red 
two times, once every 
second, followed by a 
two-second pause. The 
Power LED will continue 
flashing until the 
problem is resolved.
Processor thermal 
protection activated:
A fan may be blocked or 
not turning.
OR 
The heatsink is not 
properly attached to the 
processor.
1. Ensure that the computer air vents 
are not blocked and the 
processor cooling fan is running. 
Leave a 4-inch (10.2-cm) 
clearance at the back of the 
system unit and above the 
monitor to permit the required 
airflow.
2. Reboot the system and observe if 
there are any POST messages 
stating that one or more of the 
fans are not detected. If a fan is 
not detected during POST, 
unplug the unit, open the chassis 
and ensure that the all the fans 
are plugged in correctly.
3. If fan is plugged in and seated 
properly, and the POST message 
still appears, then replace the 
processor fan.
4. Reseat processor heatsink and 
verify that the fan assembly is 
properly attached. See the 
appropriate Service Reference 
Guide for instructions on how to 
reinstall the heatsink. Correct 
heatsink installation is critical to 
proper system operation.
5. Contact an authorized reseller or 
service provider.
Solving General Problems (Continued)
Problem Cause Solution










