My HP all in one MS214 is not powering up.

[nepras47]

when I wait for a long time, like 30 hours then it will turn on for a very short time and die again and the blue light will not come on. It all started about a week ago when the computer would just  go black, just like when electricity is turned off. It would boot up few times after that .

[BeemerBiker]

There is a disassembly video here

https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/take-aprt-the-Pavilion-all-in-o...

Blow out all dust, remove** and re-seat the memory sticks, look for any damage on the motherboard such as stains, or bad capacitors or leaking electrolytes.

Once (if) you get it working consider upgrading to Windows 10 64 bit.  Drivers to support win 10 are here

https://support.hp.com/us-en/drivers/selfservice/hp-envy-700-desktop-pc-series/5399651/model/6529884

** Turn power off, unplug, touch finger to metal part of chasses before removing memory or any other part.

[nepras47]

I did open it up and I did clean it and all, but to no avail, it will not turn on, now even for a second.

[BeemerBiker]

There should be beep codes and flashing lights.

Maybe the power supply is bad?

You might take it to be tested with the agreement to buy the power supply if that is the problem.

Do not buy a power supply, try to get it tested to see if the supply is no good

[nepras47]

I measured the output on my power supply and it is 19.5 volts and the green light is on when I plug it in. Is there a possibility that the power supply cold be still bad?

[BeemerBiker]

Seems power supply is good.

Your options are limited to DIY repair or replacing the system and salvaging as many parts as possible from the old one.