Greetings,
Welcome to the forum.
I am not a HP employee.
A checksum error means you may have a possible BIOS data integrity problem.
I would try replacing the CR2032 motherboard (MB) battery. This will also reset CMOS.
Disassemble the PC. Pull the existing CR2032 MB battery. Let the PC sit for about 15 minutes.
Install the new MB battery.
Regards