HP Elitedesk 800 Won't Switch On

[Pototea1]

Hi there, I have an HP Elitedesk 800 G1 desktop computer which was working perfectly as of last night. After shutting down I switched it off at the mains. This morning it won't power on. The white light on the front is on constantly and the green light on the motherboard is also on but no joy on actually switching it on.

- I have tried a hard reset by unplugging, holding down power on for 15 seconds then plugging back in

- reset cmos button

- taken out power supply to inspect but there are no buttons to push on this so can't see how to reset psu

When I take off the kettle lead then plug back in the power briefly comes on, power button goes green for a few seconds and the fan starts then all goes dead except for the white light next to the power button which is on constantly.

Any ideas what the problem might be?

[itsmyname]

@Pototea1 -- Any ideas what the problem might be?

The "usual suspects" are:

1. power-supply not putting out the various voltage levels required by the various components, maybe due a "power-surge" that damaged the power-supply;
2. processor 
3. motherboard

For trouble-shooting, if you are technically capable, experimenting with a different power-supply is not too difficult. It is much more complex to disassemble any computer, to try a different processor -- a task that should be left to a computer technician. It is expensive, and probably difficult, to find an identical motherboard, and to install it, based on a speculation that the current motherboard has failed.

Don't shoot the messenger, but you might spend a lot to hire a computer technician, and on replacement parts. Maybe, it's time to find a local owner/operator computer shop, that will take your computer, as a "trade-in", on a new computer.  Keep your disk-drive, so that you can copy your Personal Files onto the new computer.

Note that if you do repair your computer, it probably is not compatible with Windows 11.

After October 2025, Microsoft will not support Windows 10.  So, at that time, you'll need to purchase a new computer.  So, purchasing a new computer "now" is an option to "future-proof" yourself.

Also, your current disk-drive is probably several years ago, and it probably has been "out-of-warranty" for several years, and should proactively be replaced.

Finally, a question for you: did you purchase the computer within the last 12 months? If so, the HP Warranty is still valid, and HP will repair/replace your computer, at HP's expense.

[Pototea1 · Accepted solution]

Thanks for taking the time to reply. Thankfully I am fairly technically capable. I visited my parents today and my dad has the exact same computer. I took out his psu, put it in mine and still no joy. However my dad noticed his PC makes a click noise when you push the power on button whereas mine doesn't. The white light on his PC is also off when the PC is off whereas mine seems constantly lit. So we suspect it's down to a faulty on/off button. I've ordered a new one and it should arrive in a few days. I'll update on whether this fixes this issue - I suspect it will. My 9 year old is a bit heavy handed and uses this himself for his gaming so I think with his constant on/off use of the button probably broke it. It's several year old and thanks for the heads up about October 2025. I doubt I'll still be using this in 3.5 years.

[itsmyname]

@Pototea1 -- Thankfully I am fairly technically capable

If you are VERY technically capable, you might be able to trace the wires from the ON/OFF switch to two pins on the motherboard. Then, if you are exceptionally brave, you may use the tip of a screwdriver to very briefly "short" across those two pins, to see if that brief connection simulates the ON/OFF button, to cause the motherboard to power-on.  This should confirm that the ON/OFF button is physically damaged.

[Pototea1]

Haha, not that brave unfortunately! I've traced the wires and ordered a new part. It was only £5 from ebay so no big loss if it turns out that's not the fix. My son can live without his gaming for a few days 🙂

[itsmyname]

@Pototea1 -- My son can live without his gaming for a few days

Well said!  🙂

[Pototea1]

New power button arrived today. All fitted and as good as new!