PC will not shutdown - insists on immediately starting up again

[Rich5555]

I cannot get my PC to shutdown either from the Windows - Power - Shut Down menu or by using the power button on the PC itself.

The shutdown completes correctly and then the system immediately reboots and reloads Windows.  It does not seem to be OS related as it does the same when I use a portable version of Windows XP on a boot USB.  I have updated the BIOS to the latest 01.14 and I have tried shutting down with no peripherals connected, even disconnecting the front panel USB sockets from the board and unplugging the network cable before closing down.   I dont like shutting down by pulling the power plug but what else can i try ?

[PtomGuru]

Hello ,

Please remove the LAN cable alos

Power on the unit and at the HP screen , press F10 to enter BIOS .

Once in BIOS .Navigate to file File > Apply Defaults and Exit

This will default all the BIOS settings.

Test the unit after the change

If issue is the same , the power switch may have shorted .

[Jay_Dee86]

Greetings!

I would suggest, for this issue, to try two things. First, I would try to remove all power from the unit and hold the power button down for 30+ seconds to remove all electricity off of the system board. Second, I would try and test with a known good hard drive and see if the issue still occurs.  If neither of these produce any change in the situation, I would contact HP Elite Support at 1-866-625-1175 for a potential hardware replacement.

Best of luck!

[Rich5555]

I shall try both of those suggestions now, thank you. I did try to shut down with the LAN cable unplugged but that failed too. I shall reset the BIOS to default and try again

[Rich5555]

Ok .. reset to BIOS defaults, disconnected all peripherals including LAN cable and have disconnected HDD. Booted to a bootable USB copy of WinXP and am still getting the same shutdown routine followed by an automatic restart. Guess it's a faulty start button on the case.... or possibly the PSU but I can't test that with another power unit since the board connections are non standard on this model.

[PtomGuru]

Greetings!!

Another possibility is that the  CMOS battery is defective , not detected or not present

[Rich5555]

Actually the battery was dead when I received this unit so I have replaced it with a new one. I may just try it with the battery removed to see if that is an issue.

[Rich5555 · Accepted solution]

To update this solution, I treid to close down the PC with the CMOS battery removed and that seemed to work.  I then replaced the battery and it reverted to its old shutdown-restart sequence.  I then tried a different battery and this time I managed to get the PC to shut down correctly.  Lets hope it stays that way now.  Thank you for all the suggestions and help given here. 

[benmr3]

Having same issue.  Very frustrating.  Seeing how shutdown is a standard feature of PC's since their invention you'd think HP wouldn't be having this problem.  Vendors should give some recompense for time and energy spent on such defective, substandard devices.  Already I've spent hours trying to troubleshoot and apparently will have to spend even more.  Thank you HP for decreasing my quality of life.

[Rich5555]

Are you still having this issue now?  Mine was fine once I'd worked out it was being caused by the CMOS battery and replacing that has meant that the system will now shut down correctly when i ask it to.  I think it was also important that it was running the most recent BIOS update available.