I have a Acer Nitro 5 an515-45 its numpad is working fine but the zero key on numpad is not working

Does the main keyboard Zero 0 Key work, and why don't you use that? If you want the numpad zero 0 key to work, try to disassemble the zero 0 key and clean its internal mechanism and then reassemble the key and see if it will works. If not then check the keyboard cable connection to the mainboard if is lose or you need to replace the keyboard.

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