Hp desktop not powering on there is a light where power cord goes in the back of the screen

[Skybluedirk]

Desktop has power light at back where power cord is plugged in but nothing happens when pressing power button on the bottom of screen.

If press and hold power light comes on but then goes off as soon as you let go 

[itsmyname]

@Skybluedirk -- that lamp indicates that the computer is connected to electrical power.

It does not indicate that the power-supply is sending power to the motherboard.

For a "desktop" computer, if you are comfortable with partially-disassembling it, try a different power-supply.

For an "All-In-One" computer, I recommend that you take the computer, and its external power-supply, to a computer technician for professional trouble-shooting.

If you purchased the computer within the last 12 months, contact HP Support to open a claim against the HP Warranty. HP will repair/replace your computer, at their expense.