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for 3d printers - this sort of thing:...

Ah right - yes, desktops are a lot more robust.
Pretty much guarentee the drive in the laptop is fine.
Depending on the ,model you can just remove a panel to get at the drive, some of the newer...

use a dedicated 12v power supply. Look for psu for led lighting - same thing but more power and cheaper.

Also having 12v go into a usb socket should only fry that particular usb chip.
How old...