Computer not turning on after sleep mode (HP Pavilion Slimline s3700y)?

[jaejoongah]

 1. Product Name and Number
     • Product Name: HP Pavilion Slimline s3700y

     • Product #: NC689AA#ABA

 2. Operating System installed (if applicable) 
     • Windows 7

 3. Error message (if any) 
     • Computer does not turn on so there are no error messages seen.

 4. Any changes made to your system before the issue occurred
     • I installed new windows updates that were security related.

Here is my problem: I put my computer into sleep mode and I watched it close down. I left the computer to go run an errand and when I came back, there was no light on indiciating that the computer was even running. I am not sure if the light should be orange during sleep mode as this is the first time I have used it. Well, I tried to power on the computer by moving the mouse, touching the keyboard, and even using the power off and power on button. Nothing happens. I tried the plug to see if it was a connection issue, but that isn't it. The only thing that indicates something might be trying to work is that a green light comes on at the back of the power supply. There are no fans running, the HD does not spin as if it is starting up. It's as if the computer just doesn't want to come on anymore. I have tried many troubleshooting techniques and nothing seems to work.

My question is: Could this be a power supply issue, a motherboard issue, or a hard drive issue?

I am really hoping it is not the hard drive that keeps the computer from turning on--I don't even have to worry about booting up right now because the computer doesn't even come on to attempt a booting process. The only thing indicating life on the computer right now is that green light at the back of the power supply, though nothing else runs as it would normally when the computer comes on. I see brown marks on the side of the power supply and it was quite dusty in the computer. Could the power supply have burnt out or simply stopped working? Or could it be the motherboard doing this? Either way, could this have affected my HDD and corrupted it to where it no longer functions so I need to get an entirely new computer and or working parts?

I will be happiest if it turns out to be the power supply. Those are quite easy to replace and the cheapest. I will be quite devastated if my HDD is no longer functioning and I can't save the data on it. I am not that well versed with plugs or switches or any other signs of life that I should be looking for in order to determine the problem any further, so any help is appreciated. 

[Ray_Marker]

First lets check the settings for the sleep mode. This link will help if its a issue with the Windows

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01853693&cc=ad&dlc=en&lc=en&jumpid=reg_r1002_us...

[jaejoongah]

Okay I tried it, though this was the first thing I tried when I noticed the power light wasn't on, nor was it even an orange color that it should have probably been to indicate it was sleeping. The green light at the back of the power supply is the only thing that comes on right now. Everything else inside the computer doesn't even attempt to start coming on.

[wb2001]

jaejoongah,

Sorry about your problem, but lets try to perform the standard tests. It is very important that you follow each step.  I would suggest you do this with the case open, so you an observe the fans and the green light when you press the power "ON" button.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph06788&tmp_task=solveCategory&cc=us&dlc=en&jum...

Hopefully you can reset the PSU.

Just so you know, the slimlines use a non-standard PSU. HP part number is 5188-7520 . See example and look at plugs and measurements:

http://www.atxpowersupplies.com/200-watt-HP-slimline-power-supply-FSP200-50PLA2-SL.php

This has the plugs:http://www.buy.com/pr/product.aspx?sku=225588439&sellerid=34620860

[jaejoongah]

I tried your suggestion and the same thing occurs. I asked a friend of mine to do a test on it for me by swapping out my PSU for one of his that was working that he was not using. The computer started right up and everything shows up on the HDD. 

It's definitely the PSU that's shot. I will just have to replace it.

Thank you Ray_Marker and wb2001 for giving some helpful suggestions. I really appreciate it!

[wb2001 · Accepted solution]

You are welcome.