Hi,
When does it shut down by itself? (gaming, browsing, watching videos) Was it also on battery or was it connected to its AC adapter when it shuts down by itself?
- First, test your laptop if it would shutdown without it's battery and just connected directly to its charger.
- Next is to try another AC adapter that has the same voltage and see if the same problem will persist or not.
- If it does still shut down, it could be overheating which is causing it to shutdown by itself.
- Try to clean the inside of your laptop making sure that there's no dust stopping the fans from spinning and apply new thermal paste on both the CPU and GPU as well.