Laptop is not starting

@trendingtop you are not giving us much to work with. We would need to know what it is that your laptop is exactly doing and showing as well as what you have already checked. Does your laptop give you any sign of life?

For now, start off with the easy things. Disconnect the power from the computer by unplugging the power cord from your computer. Disconnect all external devices from the computer. Remove the battery. Now hold the power button depressed for about 30sec-1min. Reapply the AC power adapter and see if your computer does show any sign of life.

Next 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 a ammeter and see if your laptop draws any amperage from the charger. This is to verify that your AC adapter works and that you are not dealing with a totally discharged battery that can't be charged.

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. Adding images to an existing question

For now and until you can provide more details use the Lenovo Z P Series Hardware Maintenance Manual and start on page #19 to see what Lenovo suggests