Never use your laptop on a bed or a cushion or the carpet
(blocking ventilation grills underneath can damage your hard drive as heat has nowhere to go)
Never move your laptop whilst its plugged in
Tension of the power jack, might break the socket inside ( and its not always fixable)
Desktop Computers must be be protected with an anti-surge protection plug.
This stops spike of electricity damaging components inside your machine
Always do regular back ups of your files to a memory stick or external hard drive or the cloud
Back up drives can fail, so always do a back up of a back up
Do not use a computer still running Windows 7
Microsoft stopped support for Windows 7 in January 2020
Keep your Windows and Anti Virus Software up to date
Otherwise you could get hacked