HP EliteDesk 800 G1 Tower Service Manual page 218

Computer will not boot from hard drive.
Cause
Hard Drive's "Emulation Type" is set to "None." (some
models)
Hard drive is damaged.
Computer seems to be locked up.
Cause
Program in use has stopped responding to commands.
206 Chapter 9 Troubleshooting without diagnostics
Solution
Run the Computer Setup utility and change the "Emulation
Type" to "Hard Disk" in the device's details under Storage >
Device Configuration.
Observe if the front panel Power LED is blinking RED and if
any beeps are heard. See Appendix A,
on page 236 to determine possible causes for the blinking
red and beep codes.
See the Worldwide Limited Warranty for terms and
conditions.
Solution
1. Use the task manager to close programs that do not
respond.
2. Attempt the normal Windows "Shut Down" procedure. If
this fails, press the power button for four or more
seconds to turn off the power. To restart the computer,
press the power button again.
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