@mihokisic 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.
You may also have to consider replacing the battery. A depleted battery can no longer be charged. However, it should not prevent your computer from coming on, if it is connected to the AC adapter.
it is also possible that this is a bad RAM module or a bad LCD. So 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 Lenovo use the [document|41817] Let us know what you find out.