HP Envy 700-453nl randomly does not boot

[Andrea1199]

Since about 6 months ago it suddenly wouldn't boot anymore. 2 seconds after I press the power button all lights go off, a 6 beep pattern keeps playing and after some iterations it turns itself off.  Sometimes it doesn't even beep and turns itself off after a few seconds and then tries to reboot itself, failing.

A few days ago, after months in which I completely gave up on it, I tried bringing it with me at my workplace, with the intent of performing some tests to see which component might be faulty. To my surprise, it booted like nothing ever happened. I tried turning it off and on again a few times and it always booted correctly. So I thought that maybe my AC adapter or my plugs at home were to blame. I changed cables and plugs and... It wouldn't boot again. 

In the last few days, in a desperate attempt to revive it, I tried many things: I cleaned it with compressed air, I removed RAM sticks (one at a time to see if they were faulty), I removed the GPU, I tried pressing the power button for 15 seconds and more with the pc unplugged. None of it worked. Today it randomly booted and worked just fine for an hour, then I tried turning it off and on again and the 6 beeps returned. 

I'm not an expert by any means, so if someone had a similar problem and wants to help, I'd be very grateful. I know it's quite an old pc, but if it's feasible I'd like to fix it

[Bill_To]

Hi @Andrea1199 

Welcome to the HP Forum.

You seem to have an intermittent hardware problem. This HP Site lists common POST error codes.

I don't see a linear six beep error code but you could check: a two: four, a three: three, or a four: two error code. None of these codes seem to apply in your situation but this is what HP lists if you have an error which sums to six beeps.

It is very unusual to see the PC worked fine when testing it at your workplace. Did you use your: monitor, mouse, and keyboard when testing the PC at work?

The factory power supply could be failing.

What happens when you start the PC with only a monitor connected. Also, only connect one stick of RAM. Try each stick of factory RAM, one at a time, in each slot. Disconnect a discrete graphics card, if applicable, then (use onboard graphics). 

Disconnect storage devices, and front panel USB including the card reader. In other words, run the PC in a minimum configuration.

Have a local PC Tech take a look if you can't isolate the bad component.

Regards