|Have you, or is it possible anyone else has....|
- dropped this laptop, or otherwise subjected it to a physical jolt ?
- spilled liquid on it, or exposed it to liquid such as rain, or sprayed it with liquid ?
Have you had a power failure event while the AC adapter was plugged in since the last time the built in keyboard worked properly ?
If the answers to all those things is definitely NO....
Check for keys on the built in keyboard that are stuck in the depressed position.
If ALL the keys on the built in keyboard work, and it's just SOME keys that produce the wrong characters on both the built in keyboard and the USB keyboard....
- you may have the type of keyboard you're using set to the wrong type in your Windows settings - in that case the keyboard mapping is wrong - SOME of the characters printed on the keys don't match the characters for the keys for the keyboard type.
Control Panel - Classic view - Regional and Language Options -
Regional Options tab / window
Is that set correctly ?
Languages tab / window
Click on Details
Is the correct keyboard listed for the country you bought the laptop in (or the country it was intended to be sold in) ?
E.g. if the country you bought the laptop in (or the country it was intended to be sold in) is the US or Canada, you use only English, that should be set to
English (United States)
- much less likely, some laptops have a key combo, e.g. Fn + some other key, that toggles the keyboard on / off to produce different characters than are printed on the keys for SOME keys.
In that case as well, a USB connected keyboard may produce the same wrong characters.
The info about that is in the Owner's or User's manual for the laptop model or model series.