I have not seen the Acer 6312 in that case and colour scheme before.
If you can't get all keys working on the keyboard, save the key caps! From the label, I suppose that they are in Swedish/Finnish layout under the blue stickers.
The
Acer-switches are mechanical in the same way like the buckling springs in a Model M, in that there is a spring and hammer on top of a membrane in each one.
If there is a row or column of keys in the matrix that don't work, then I would first search for if there is some corrosion on that line or if the contact could be out of alignment. If a line is broken, it could be repaired with a "circuit repair pen" or a piece of metal tape. If it is the odd switch here and there, I would open those switches, and perhaps replace with a switch from a less used key.