My HP Touchscreen won't power up or boot

[Ronnie444]

I was using this older PC and it suddenly went black, nothing. I have two of these Touchsmarts so I was able to check several things but nothing has worked. I have my green light at the power port but I do not get a blue light at the power button. Here is what I have tried:

1) I tried a different power brick from the other HP. No difference

2) I removed the HD from the bad unit and it booted up fine in the other HP.

3) I removed the CPU and switched them.  no difference

4) I switch the memory cards, no difference.

5) Installed new bios battery, no difference.

6) Here is the biggie........I ordered a new mother board and just installed it, no difference.

When the power button is pressed, it powers the fan and the green light is on at the bottom of the board. There is no light at the power on button and there is no sound made like it is trying to boot up. There is no white blinking light to indicate the HD is working. The fan works like normal and does not over speed or anything. Everything is clean and dust free. I have tried to bring a prompt up on the screen or a bios update, nothing. The green light does come on for the DVD drive and it will pop out.

Obviously I am missing something. Probably an easy fix and cheaper than the $90 new mother board that i installed. Any suggestions would be appreciated.

More details.....I disconnected the cooling fan and then powered up the unit. With the fan gone I could hear the hard drive spinning up but still no blue light on the power switch, nothing on the screen, no sound, and no blinking white light on the mother board to indicate that the HD is booting up. I also inserted a disc I had from an old Windows XP (Unit came with Win 10 so no disc available). The disc seemed to cycle and after a period of time was ejected by the disc drive. There was still no evidence of the motherboard coming to life with a blinking white light and nothing on the display.

[Ronnie444]

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