My laptop is not turning on and do not show the battery light

@ankith71707 obviously a power issue. Could be related to failed MOSFETS on the motherboard but it can also be a simple thing like a failed DC-in jack etc. Start by checking the easy things.

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. Make sure there is no corrosion, debris etc. that prevents it from working. 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.

After that this might just turn into a board level repair. For that you have to make sure that you have the proper tools as well as good skills. It will also help if you can post some good pictures of your motherboard as well as telling us exactly what the board is. On the Lenovo computers, the number will be on the top side (the side that faces the keyboard) You will have to remove the motherboard. Use this ThinkPad R61 Hardware Maintenance Manual to work on your computer Adding images to an existing question