!!
critical HP
Error Code Red LED flashes continuously without pause between blinks
System unable to power on - no hardware activity detected
? What Causes This
Total system board failure or improper cable connections.
✓ How to Fix It
- Check and re-establish proper cables and connections.
- Repair/replacement of entire unit required if issue remains unresolved.
Source: page 3 of the official manual
From the manual
This error code appears in:
HP Compaq Pro 6300 SF Desktop