What inspections and tests should I perform on a second hand laptop to minimize the risk of buying a damaged machine?

Question

I'm out to buy a used laptop and wonder what I should look for to avoid buying a damaged machine.

What I've already thought of:

1. Visual inspection (dropped etc)
2. Test SSD (how can I do this?)
3. Test touchscreen, tochpad and "joystick".
4. Test keyboard.

What more should I think of and what tools are good for performing such checks? Preferably it should be a bootable tool, so I don't have to install anything on the laptop and can test it before I buy.

Answer 1

The following is intended to be a canonical list of things to check when buying a second hand laptop. Please pitch in!

• Visual inspection: Check for visual damage. Does it looks like the machine has been dropped etc. It might not matter for function, but if the machine looks rough, chances are that the owner has not taken so good care of it in other ways too -- and dropping can do damage that's not visible.
• Listen if the system fan is humming. A common fault of used laptops is that the cpu cooler fan's bearing is worn out and that it will be noise. But if replacements parts are available this might just be a way to get the laptop cheaper.
• Check that the headphone jack works.
• Check that the internal mic and mic jack works.
• Check for darker spots and scratches on the screen.
• Test the keys of the keyboard.