Startup Problem HP dv6700

[imSteve]

So, basically, I'm having an issue getting my laptop to start up.
I had taken it apart to clean it, and once I put it back together it wouldn't start up. Before I had taken it apart, it worked fine, but would get hot. The reason I took it apart was to remove the dust from the fan.

Here's the problem:
I press the power button, and all the lights come on. The fan starts spinning, and before the screen can come on, it shuts down. It doesn't attempt to restart itself.
A couple of times, it got as far as displaying the 'HP' logo on the screen with the "F12 for Setup, Safe Mode, etc., but never past that, except for one time that I left the HDD out and it displayed "No operating system found..."

I have tried:
Removing the CMOS battery for a while
Removing one of the memory chips
Cleaning and putting new thermal grease on the CPU

If anyone has experienced this, or similar, and has any idea how to fix it, it would be greatly appreciated.

 

[imSteve]

Ok, now the plot thickens...

I have everything plugged in, HDD, Memory, etc., except the battery. The power cord is plugged in, and the light around it is blue. When I pressed the power button, it flashed on, but my laptop didn't start up, so I figured, for whatever reason, that it wasn't getting enough power. So, I plugged the battery in, and tried turning it on. It worked. Booted up fully, logged in, able to access folders and files.

Now, at the point of this, not everything is screwed together in place. The mobo isn't screwed into the shell, the keyboard isn't clicked in place, the monitor isn't screwed on, etc. I'm going to turn it off and set everything in place, I'll reply if it works or not, but I still have the feeling that something is wrong.

 

[NBClue]

Quote: "...except for one time that I left the HDD out and it displayed "No operating system found..."

have you tried replacing hdd? have you tried to put yours hdd into a external case and connect it to another computer via USB and see if you can access your data?

EDIT: OK I see you managed to work it out. Did you find out what was the cause of the problem? I know this might sound silly but sometimes switching memory can cause similar symptoms.

 

[imSteve]

Well I didn't quite get it to work yet.
It works when its all in pieces, but not when it is all together. I went through, piecing it together one by one, and testing in between. I had it working until I tried to put the Power Button / QuickPlay bar into place. It was on, then as soon as I tried to click the bar into place, it shut down.
My guess is that maybe my laptop thinks the lid is shut, because my settings tell it to hibernate when I close the lid, but I don't know where that sensor is to test my theory.

 

[imSteve]

Figured it out. Just needed a new KOTL ribbon cable for the power button board.