Hp dc5100 sff. pass ps botton green led will come on let go of botton led goes out computer still dead. green led light on motherboard and tried power drain.

desktop small form factor, SFF, (not silly fat frog)
no statement as to where lamp is, I'll guess, FRONT.
just the light bothers you, only..?
why not RTM read the manual to learn what it means.?
so where is said LED lamp, ? front of case on the SSF case?
HP calls it, and searches only work with this.
HP Compaq 8000 Elite Small Form Factor PC./
im reading your manual now for you at HP.com
my guess is lamp 5, (pwr) is not green now but is red
green means power ok, red means, not ok.,
page 2:
if flashing , the flashes are codes, what is your flash code if flashing
if not this LED then say which one?
green on 5 means ok. power ok, no errors. red bad.



http://h10032.www1.hp.com/ctg/Manual/c01957825


the flash codes are here. page 47 ,

http://h10032.www1.hp.com/ctg/Manual/c01960471

you stumped me, the service manual shows no steady red.
why not ask at Hp.com

more manuals here
https://support.hp.com/us-en/product/hp-compaq-8000-elite-small-form-factor-pc/4065894/manuals


hp forum here.
http://h30434.www3.hp.com/

Why would you want to try to repair a working green LED?
But you need a manual, to check what the blinking light means. See how it flashes, because the board is trying to tell you what is wrong with these flashes. Like perhaps bad voltage, or bad RAM or ROM? or lost all settings.

You removed the HDD and tested? Did you swap out the ram? Have you swapped out the PSU? Reset ALL the PSU connections?

It slides right back and off. Make there is no security screw or tab in the back.

to get a driver for HP Compaq dc5100, try to this link to download the drivers; http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=447291&prodTypeId=12454&prodSeriesId=447279&swLang=25&taskId=135&swEnvOID=2094

Most motherboards come have reset buttons on them, unplug and press the reset botton. Your power supply may be gone. Try replacing the power supply.

You can download the Drivers and Software from the below link:
Select the Operating System installed in the Computer and download the Drivers, Software.

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?prodNameId=447291&lang=en&cc=us&taskId=135&prodTypeId=12454&prodSeriesId=447279
Hope this helps.

open the side cover of cpu and you will see inside motherboard ther is one lithium cr2032 battery is there that is cmos battery.

its definately not the motherboard, actually when a ps is about to spoil it starts giving that problem and also, the memory cards are also able to cause this problem too. but first, plz try changing ur ps and see if it works..

try to reset BIOS by CMOS battery from motherboard and insert again...if not worked then..ur motherboard needs to be replaced...