HP Pavilion Slimline 400-034 Won't Boot = No Power Button LED - No Display

[TonyLudwick]

When I press the power button, the LED in the PowerButton does NOT come on, and I get nothing on the monitor, not even a BIOS or Boot Option Screen.  But everything seems to be getting power including hard drive, DVD, fans, etc.  Here is what I have done so far:

Tried different monitor.

Tried using other video port.

Tried using add-in video card.

Tried removing components one by one to force beep codes if memory was bad, or identify the component that might be causing the problem by process of elimination.

The monitor seems to know when it is connected to a video port, it's just that the machine appears to be not sending any information to the video card.

Pulled the power supply and had Geek Squad test it, and its good.

Then here's where things started to change:

Removed CMOS battery.

Cleared CMOS with jumper.

Reinstalled CMOS battery.

Attempted to boot machine with monitor connected to first video port, no go.  Power Button LED still did not come on, and machine did not boot.

Attempted to boot machine with monitor connected to second video port, no go.  Power Button LED still did not come on, and machine did not boot.

Unplugged power cord from power supply.

Pressed power button to drain power from unit.

Plugged power cord back in.

Pressed power button.  

Power button LED came on, and machine booted.

So I thought I had it fixed, so I applied windows updates, did virus scan with defender, did malware scan with Malwarebytes.

Tried to re-boot machine.  It would not reboot.

Pressed and held power button in until fans, etc. turned off.

Pressed power button, no power button LED, fans, hard drive etc got power, machine did not boot.

Unplugged power cord and presssed power button again to drain power.

Plugged power cord back in.

Pressed power button, Power Button LED came on and Machine booted.

Went into Windows 10 settings:

Disabled quick start.

Set monitor to sleep at 10 minutes.

Set system to sleep never.

Changed power button action to shutdown instead of sleep.

Did normal ShutDown fro Windows Start Menu.  Machine Powered Down.

Tried to power up the machine again with no success.  Power Button LED Not on,  Fans, Hard drive have power, nothing on screen.

Again tried :

Unplugged power cord and presssed power button again to drain power.

Plugged power cord back in.

It didn't boot this time or any following times.

Pressed power button, Power Button LED remained off, Fans, Hard drive have power, nothing on screen.

I am frustrated, tired, and stumped.

Any Ideas?

Thanking you in advance.

Regards,

Tony

[Malygris1]

Hi there @TonyLudwick,

May the Forums be with you!  I understand that your computer is not starting properly.  I am happy to give you a hand with this.

Considering the things you have already tried, I would prefer that you do hardware tests to see if any particular component is a twitchy, but right now that is not an option as it is not starting for you.   Have you tried using a direct connection to a different electrical outlet to see if maybe the circuit is part of the issue.

Also check in this document and see if there is anything there that may help: HP Desktop PCs - Computer Does Not Start (Windows 10,8). If you get to the end and there is no change, then as recommended in that same document, please use the following http://www.hp.com/contacthp, fill out the form, create a case for your issue and then use the provided information to contact HP.  

Please let me know whether that works for you, and if it does resolve your issue, please mark this post as a solution. Kudos would also be appreciated.

[LarryC5]

Did you get this problem resolved and if so if you don't mind what was the solution.  I am having the exact same problem.  I did everything you outlined and got it to start.  After putting it back together it's back to not starting/ booting although the ON LED now always comes on.

Any help would be appreciated.

Thanks,

Larry

[A4Apollo]

Hi! @LarryC5, Welcome to HP forums.

I understand that you are unable to boot into your PC.

As you mentioned that you see the power led on your PC.

Kudos to you for trying out few steps before reaching out to us.

Did you make any software or hardware changes on your PC?

Have you tried connecting the CPU to a different monitor?

Please try the steps recommended below.

Many startup errors and other problems can be resolved by decreasing the amount of power stored in hardware components. Decreasing stored power is sometimes referred to as a "Hard Reset." Use the following steps to perform a hard reset on a computer:
Turn off the computer completely; disconnect the power cord from the back of the computer.
With the power off and the power cord disconnected, press the power button on the computer for 5 seconds. The power light indicator on or near the power button might turn on briefly but then go out.
Reconnect the power cord and turn on the power.
If the computer starts, you are done.
If the computer still does not start and exhibits the same problem, continue the troubleshooting.

Refer this article to further troubleshoot no boot issues.

I'll keep an eye out for your response.  

I hope you have a great day! 🙂

[LarryC5]

I have tried all the things on the HP help sites to no avail.  If I force it to shut down by holding in the power button for 5 seconds and then restart it sometimes the display will start, most of the time it won't.  If I do this too many times without success some tims the power light will then not come on.  I can fix this by taking out the CMOS battery short out the connector terminals replace the battery and then the power lights operates again.  If I restart the computer once I get it started with a working display sometimes it will restart with a functioning display sometime not.  If I put it in sleep mode so far it seems to always start back up with a functioning display.

[TonyLudwick]

I was able to fix the problem.  Make sure that your CMOS battery is good.  When the machine does boot up, go to HP's website and download the latest BIOS patch.  Re flash the BIOS with the latest version.  If You are already at that version, Re Flash it anyway.  I believe that the BIOS firmware programming was corrupted by a power outage, fuctuation in power, etc.  I found out the user had a habit of pulling the power cord out of the wall with the machine powered up.  After I was able to flash the BIOS, he machine has worked ever since.  Hope this helps.  Let me know what happens.

If you can't get the PC to boot up, remove the CMOS battery, clear the CMOS using the jumper on the motherboard, reinstall the battery, then try booting the machine.  If it doesn't boot, try doing the same thing again, only leave the battery out until you boot it up.  Then reinstall the battery with the machine powered up.  You will have to look up the schematic for the motherboard to identify the jumper as well as the CMOS clearing procedure.  

Regards,

Tony

P.S.  Sorry that I forgot to post the solution that worked for me.

I

[LarryC5]

Thanks Tony.  Refreshing the BIOS did the trick.  My machine was hooked to a UPS that for some reason started to turn on and off which must have caused a power surge and corrupted the BIOS.  Your fix definatley made my day.

Larry Colwell

[TonyLudwick]

Great to hear that.  I am glad that I was able to help.  I know that I had messed with the machine that I was working with on and off for about a week or so.  It was one of the most frustrating problems I have ever come across.  The Jose Cuervo company made some money off of me that week.  With the way the power button led was acting, I thought for sure it was a bad power supply.  But I had it tested and that was not the case.  I tried all kinds of (process of elimination) troubleshooting, removing components one at a time, memory, etc.  Then it finally dawned on me that on the times that the machine would not boot, I was not even able to get into the CMOS/BIOS settings, It wouln't even get that far, which told me that the CMOS/BIOS firmware for some reason was unable to run.  So I thought maybe if I re flashed the BIOS, that would do the trick, and it did.  I just wish I would not have taken a week to think of it.  LOL!  Anyway, again, I am glad I was able to help,  Have a good day.

Regards,

Tony