HP Pro 3420 Maintenance & Service Manual page 91

"Invalid system disk" message is displayed.
Cause
A diskette that does not contain the system files needed to
start the computer has been inserted in the drive.
Diskette error has occurred.
Cannot Boot to Diskette.
Cause
Diskette is not bootable.
Diskette boot has been disabled in Computer Setup.
Network server mode is enabled in Computer Setup.
Solution
When drive activity stops, remove the diskette and press the
Spacebar. The computer should start up.
Restart the computer by pressing the power button.
Solution
Replace with a bootable diskette.
1. Run Computer Setup and enable USB device in
Storage > Boot Order.
2. Run Computer Setup and enable USB device in
Storage > Storage Options > Removable Media
Boot.
NOTE: Both steps should be used as the Removable
Media Boot function in Computer Setup overrides the Boot
Order enable command.
Run Computer Setup and disable Network Server Mode in
Security > Password Options.
Solving Diskette Problems 83