HP Notebook - 15-f272wm (ENERGY STAR) is the model of my notebook I think. I'm not very computer smart so bear with me, the last time my laptop had been turned on was around 4 months ago. The only light I see on it ever is the charger light, either orange or solid white. When I pressed the power button, all I hear is a very quiet, slight squealing noise - it sounds higher pitched and then goes to a lower pitch. You can only hear it if you press your ear against the keyboard. No sign of fans or anything. I bought a new battery thinking it needed replaced, still nothing. I have tried EVERYTHING to try and get it to turn on, nothing works. I have watched numerous videos. Read about a million things online, nothing. It doesn't even turn on without the battery and just the charger, and I don't know what to do with it at this point. I don't have a warranty on it anymore. Please, any suggestions on what I should do?
That sound is not good, sounds like electrical noise which can often be from failed components. Remove the battery and the CMOS battery from the motherboard if it has one, hold in the power button for 30 seconds. Plug in wall power only and see if it turns on. If not, plug things back in, remove the ROM and try to turn it on. If you don't get any sort of life or error beeps or lights, it's pretty much guaranteed motherboard is bad.