Like everyone else, i opened it to clean out the fans. Took off covers, keyboard, mem cards x 4,, 2 top and 2 bottom. Put it back together , hit the button. It turns green and for a fraction of a second, the fans bump,, then nothing but a green light. No beeps no error message, in fact the screen doesnt have a chance to come on, its still short about 2 seconds before it woul kick on. All i can think is either the cards arent in the correct spots so it cant find the boot, if it works like that idk, or maybe not having a long enough screw in the right spot so it isnt grounding right. And i dont know if they work like that either.
You must be referring to the RAM cards. The order for these is generally not important. If all the RAM cards are the same, there is no ordering. If your architecture is "dual channel" and the cards are different, they may need to be paired properly. "Cleaning" can cause lots of issues and I see problems created by doing that frequently. If you didn't follow good ESD precautions, you may have damaged something. Did you unhook any internal connectors? That can also create problems. You should always have the service manual for the laptop you are working on and follow that.
I believe i have the answer. It worked for me anyway.
Have your laptop open to where you can get ahold of the wires that plug your power button to the motherboard.
Now hit the button to power it up, and immediately unplug the button. Give it about ten seconds and it should boot.
What i had happen was, the wires being so tiny, they got crushed when putting back together after cleaning , so either replace the button or attempt to twist the wires so they make a good connection again.