!
error HP
Error Code Red LED blinks 3 times every second followed by a 2 seconds pause
Processor not installed or missing.
? What Causes This
No processor installed or incorrectly seated.
✓ How to Fix It
1. Ensure the CPU is properly installed and seated on the socket. If necessary, contact service technician for installation assistance.
Source: page 2 of the official manual
From the manual
This error code appears in:
HP Compaq Elite 8300 Small Form Factor PC