Please open the device, remove the battery and check for anything loose inside. Shaking it and it working sometimes, suggests that there is a loose or maybe a dirty connection. If this is old, the battery terminal or where the battery connects may be dirty; cleaning can help provide a better connection. Try another battery to confirm the issue is not a flat battery. It is unusual to have it work sometimes after shaking. Please check to confirm there is nothing loose inside.

A laptop shutting down every twenty minutes is likely caused by either: 1. Running from battery, not mains, and battery only lasting 20 minutes, or 2. If running from mains or battery is not discharged, it may be overheating and shutting down to protect itself from damage due to excessive heat. This is more likely at the laptop is old. The solution is to power off, remove the battery, clean the fan completely, check for any damaged components such as capacitors which may have bulged, indicating not working correctly. 3. If the fan was clogged or very dirty, clean and replace the battery, connect the mains and try again, it should last longer than twenty minutes. You may be able to find a new battery to replace the worn out battery. I run some very old laptops without a battery since I can run from the mains.

Usually knobs on many appliances such as this come off by simply pulling them gently out horizontally from the appliance. Try to remove them slowly by pulling evenly on both sides at the same time.

Please try the following to see if they help. https://h30434.www3.hp.com/t5/Notebook-Boot-and-Lockup/HP-Chromebook-14-Not-Booting-Up-At-All/td-p/8729576 https://support.hp.com/us-en/document/c00476202 https://support.hp.com/us-en/help/computer/power-boot-issues

Please see this post. PS3: extremely noisy fan

Laptops are designed to use both battery and mains power. While they can and frequently do run on battery only, the power drain from the battery depends on the battery condition and the battery load, such as are you using an intensive game, video editing or several power hungry processes. Laptops using mains and battery do provide more power and give better results, as shown in the Geekbench 4 64 bit scores. As a 2012 Mac is using a ten year old processor, I'd recommend a new Mac with M2 chip that will last for another ten years.

You can buy a replacement screen from Aliexpress. https://www.aliexpress.com/w/wholesale-redmi-note-5-pro-screen-replace.html There is a guide for Xiaomi 3 on how to change the screen. Xiaomi Mi 3 Touchscreen Replacement There are a number of guides for other Xiaomi models. I suggest reading a few before starting, purchase the tools needed from Ifixit and the replacement screen, then write your own guide for others wanting to replace their screen. I hope that this helps you get started and also contribute and help others.

Another option to replacing the fan is to remove the fan, clean it well, check that the motor is ok and to gently lift the plastic fan blades from the spindle, put a small drop of oil on the spindle, replace the blades. It is likely that the fan is attached to the heat sink, so you need to clean the heat sink, including where it contacts the CPU and GPU. Apply fresh thermal paste, replace the heat sink and power on the laptop. Watch the temperatures to verify that temperatures are within normal ranges. I have replaced my fan three times, and only recently found that it can be fixed without replacement.