I’ve found that googling the model of your laptop + the problem your having will bring up message boards of people complaining about the same problems, and the people who’ve answered them may help you find out what you can do to fix it. I used to have a laptop that did that, it turned out to be a bad connection between the battery and the power supply (It was many many years ago, I may be misremembering). I gave up because their tech support was atrocious, and got a new once (of a different model!) since that old thing was a dinosaur that needed to be put down, anyways.