The BIOS "power on after power loss" setting will not work if the computer was gracefully shutdown with a UPS. Once the desktop is shutdown/powered off, it will not automatically power on again. Normally, you will need to physically press the on button - which is not always practical. With the current HP 8200 BIOS, the Desktop PC will only power on after power loss if it was ON at the time of power loss.
But there is a clever solution, which uses your router to turn it back on again - well suited to unattended small business file server setup using Elite series HP desktops.
Hardware set up
1.Connect your router and desktop to the same UPS.
2.The router must also be connected to the desktop via ethernet cable.
(This is important for WoL as it will NOT work with wireless USB adapters.)
Software setup
1. Enable "Wake on LAN" and "Power on" after power loss in desktop BIOS (Wol) as per link
https://support.hp.com/au-en/document/c04742238
2. Go in to Windows device manager, find your network adapter, and turn on "Allow this device to wake the computer", but untick "only allow magic packet to wake computer"
3. Set up UPS to hibernate after about 120sec
4. Set UPS to power off after another 30sec
This is what happens on Power Loss
1. UPS will trigger "shutdown /h" in windows. Status of open programs and files are saved to the SSD/HDD and the desktop powers down as per normal shutdown.
2. UPS will then cut power to both router and desktop. Everything is now completely safe, unpowered and off, patiently waiting for mains power to resume : )
3. When main power resumes, the UPS will turn on
4. The router will power on the and activate WoL in HP desktop
5. Desktop will power on, and restore previous state of apps and files.
Tested and working perfectly with HP 8200 and Eaton P5s UPS.
Any questions, please ask
Paul