If you see the light come on near the power input jack, that tells me that the charger is good and that the jack is also good. I have seen the internal wires fail on these in the past (IRRC). Yes, you will need to open up the laptop to resolve this. Please pay attention to the power input jack location. If the jack is in good shape (I think it is) then check the area for either a set of wires going to another location from the power jack sub-board or for any broken connections or components around the area of the power jack if it is part of the main motherboard. Start there and report what you find. If nothing, we'll look further.