Edit: Laptop went into service repair and they replaced the keyboard.

Hi everybody,

Im having a pretty irritating issue that suddenly a few keys aren't working anymore.
The keys that are not working:
- a
- q
- 1
- 0 (on numberpad)
- ~
- tab key

Under a few circumstances the keys do work. When pressing shift in combination with the not working keys. Pressing another key and quickly pressing the key that is not working. In the Bios the keys also do not work except for doing the actions above.
I already reinstalled the keyboard driver (standard ps/2 keyboard), did a full windows reset, removed and reinsert the fysical keyboard cable and cleaned the keys.

Somebody knows how to fix this or is it time to replace the complete keyboard?

Thanks in advance.

Model: FX502VM-FY250T
Bios: 307