Desktop won't start; blinking green light

[krlkrvr]

I haven't read all the posts, so I hope this isn't a duplicate. I also haven't tried the hair dryer solution, but am intrigued. Just simply unplugging the motherboard connector and plugging it back in did not fix the problem for me.

The fix that has worked for me with two different HP computers is a variation of unplugging the power supply connector from the motherboard. To start, you can leave the computer plugged in to the power outlet (voltages in the case are not too high, so there is not much risk of shocking yourself, just don't stick bare metal into the power supply willy nilly; also try not to short any other connections unintentionally--you won't get shocked, but you could damage the PC). Now, open the case, and unplug the 20 pin power supply connector from the motherboard/mainboard. The next step is to use the commonly known trick to turn on an ATX power supply--that is, take a wire or paper clip and short the green wire in the 20 pin power supply harness to any of the black ground wires. When this is done, the power supply will turn on and the green light will go solid.

Leave this green wire to ground wire connection for at least 30 seconds (the power supply will remain on during this time--you'll know because the fan in the power supply is on, and the connected hard disk drive and optical drive in teh computer spin up). Now remove the connection. The power supply should turn off, but the green light should remain solid. For the next step, there are two possible outcomes. Try plugging the 20 pin power supply connector back in to the motherboard/mainboard. If the power supply light remains solid green, there is a good chance that the problem is now fixed. Try turning on the computer and using it normally. This is the best and simplest outcome.

For the second possible outcome, if when you plug the 20 pin connector back in to the motherboard/mainboard the green light goes back to blinking instead of staying solid you will need to try this process again from the beginning, but take a slightly different approach when you get to this step again. Once you remove the wire shorting the green and black leads, make sure the green light stays solid. Now, instead of pushing the 20 pin connector in to the motherboard/mainboard socket in one step, push the connector in slowly and lightly, only until it starts to make electrical contact. You will know when this happens if the computer starts to turn on, or if the computer turns on when you push the power button. Allow the computer to continue turning on/staying in the on state while you are lightly holding the 20 pin connector in the socket. If the computer remains on for at least 45 seconds or so, go ahead and try to push the 20 pin connector all the way in until it clicks. If the computer remains on and the green light is solid after snapping the 20 pin connector into the socket, the problem is likely fixed. This may take several attempts, since when you are lightly holding the 20 pin connector in, it often disconnects and the power supply reverts to blinking; or you may accidentally push the connector in too soon, also causing the power supply to revert to the blinking green LED state. You basically need to nurse the power supply through the transition of turning on the computer for some reason. Once it reaches a steady state, it seems to be much more tolerant to completely snapping in the 20 pin power supply connector. After you are able to snap in the 20 pin connector and maintain the solid green light, the unit is generally stable again until power from the wall is interrupted for a significant period (see below).

A few notes:

1) My experience seems to indicate this problem is a flaw in the OEM power supply provided by HP. I've seen this in an OEM Bestec power supply, and also in an HP computer with an OEM power supply from another vendor. Both power supplies had the unusual green LED, and both had this problem. Once the symptom starts to appear, it will basically happen again any time the flow of power from the electrical outlet to the computer is interrupted for any significant length of time. Each time the problem starts again, this fix has worked for me. I've seen this occur repeatedly on a power supply for over 18 months, and the power supply is otherwise still functional, so it doesn't seem that the blinking green light is an indicator of imminent power supply death. This problem doesn't seem to happen in very new HP PCs, only those that are a few years old.

2) On at least one occasion, this fix resulted in a solid green light, and the computer was seemingly in an "On" state, but the light/LED indicating "Power On" was still off, and the computer was not starting normally. Also, holding down the power button did not get the PC to turn off as is normally the functionality. In this case, I avoided having to open the case again by just unplugging the power cable from the back of the power supply very briefly (enough for the computer to turn off), and then immediately plugging it back in. The green LED stayed solid, and the next time I powered the computer it worked normally.

3) My limited observation seems to indicate the speed of the blinking green LED may be related to how far gone the power supply is with regards to this problem. For instance, if you see this on an HP PC with a very fast blinking green LED (the green light may blink so fast it almost appears to be on solid), it's almost certain that you can just plug the 20 pin connector in and the green light will stay solid. PCs where the green light is blinking more slowly seem to require having the 20 pin connector lightly held in for a while to nurse the power supply to a steady state. Maybe if this fix helps other users, they can confirm whether this observation seems to hold in general.

This fix seems fairly repeatable for me, so hopefully this will help others. If you try this fix, please post whether it works for you or not.

[llovec]

Had a power outage now my wife's computer doesn't work.

Blinking light. When unplugged it becomes a slower blinking light.

I use to be a computer tech (self made) and the first thing that came to my mind was to replace the CPU.

I looked online for a replacement CPU ($18.95 + S&H).

I read forums where ppl replaced their PSU and it still didn't work but the light is now a solid green.

Then I came across this forum where are first they were talking about some solutions until in the middle of the 1st page I see this seemingly "wise tale", "witch craft", "wolf ticket" of a solution..........needless to say I was intriged (LoL).

So I got my niece's blow dryer when she was @ work (which is a good thing because she would have questioned the sh*t out of me being a big black b a l d man).  After about a minute WHALLA!!!!  The light turned green and I was able to power up my wife's computer (she didn't even know it wasn't working).

Cudoos to the genius who lucked out on this solution!!! BRILLIANT!!!

[AvorHarp]

I thought that HP never break, I must be very naive person.

[instinctive1]

I have had this problem several times. Unplugging the mother board main power worked once. After that I had to unplug everything from the motherboard, that worked 3 or 4 times. Then that would not work either. I did not have a hair dryer but set the tower on a crate in front of the fan on my wood stove with the power supply towards the warm air. It works every time. 10 or 15 min and the power supply is warmed up and it turns right on. Thanks

[Defcon1]

I am looking through all the posts and my issue is close, but not exact.  When my slimline supply is removed from the PC and it is plugged into the wall, the light remains solid and the fan does not run.  I jump with a paperclip and the fan runs and the green light flashes off and on.  Once the unit is plugged back into the PC and hooked up to the MB and plugged in the green light will remain solid but the system will not power on.  Also if I remove the supply, jumpstart it, and hook up my cd-rom, the cd will run just fine.  I have checked the voltages and they all appear within range.  I have unhooked the cpu fan, the ram has been removed and the HD also removed.  It still will not start.  I beleive I have a MOBO issue???

[lashawn877]

I tried the blow dryer absolutely works!!!! i am so happy, thanks to who ever posted that.

[Zandu]

another thanks to the blow dryer genius!

[momof6]

I just tried this after going thru all the troubleshoot suggestions (unplugging the motherboard power cord while the computer is plugged in). It worked. THANKS!!!!!!

[jongarcia88]

Hair dryer trick worked like a charm THANKS!!

Within 2min light become solid green and PC was able to start.

It is a great trick while waiting for my new PSU to arrive

[RiverRVers]

Yesterday my husband turn the power off to put in new receptacles and the pc was on.  After turning breakers back on my pc would restart.  My pc is 9 yrs old and thought for sure the mobo was fried or seomething and sure didn't want to buy a new puter at this time,   then I found this forum and It's amazing.  I used the hairdryer technique and  now my 9 yr old pc works.  Thank you Forum for the assist.