In my laptop, is not turning on? Or powering on

@abhinav46976 your question is a bit hard to decipher. It sounds like your computer does no longer turn on and that no LED is lit. I would start by checking the basics first.

First you want to check your power supply. Make sure it has the proper voltages. Check to make sure that connectors are not bend etc. Check the DC-in jack of your laptop. Clean it of any debris etc, use a few puffs of air to clean it out. If none of this works, get an ammeter and see if your laptop draws any amperage from the charger. After that, you need to check and see if your motherboard even gets power. For that of course, you need to open it up. Post Some good pictures of what you see. That way we can see what you see.

It is also possible that this is a bad RAM module. Remove the RAM, clean the contacts with a pencil eraser. Do it gentle so as to not destroy the module. Replace it and restart. If you have more than one module, remove it and just leave one connected.

To work on your laptop use the Compaq Presario CQ40 Maintenance And Service Guide and this 기존 질문에 이미지 추가하기 to add images. Here you will find that your computer uses a dedicated DC-in jack. I would suggest that you start measuring the voltage on that, with the AC adapter connected. Let's see if your computer gets power. After that we can help you further with measuring the voltages aetc, but we will need to see your motherboard.