!!
critical HP
Error Code 7 blinks, 1 blink every second followed by a 2 second pause
System board failure. Invalid ROM based on Checksum.
? What Causes This
ROM corruption or system board error.
✓ How to Fix It
Clear CMOS and perform a reset if the issue persists, replace faulty components.
Source: page 2 of the official manual
From the manual
This error code appears in:
HP Elitedesk 800 G1 Small Form Factor PC