If you search on the internet, you should be able to find instructions or a video (youtube?) on how to remove and replace your keyboard.
Embraced Solutions advice is good and worth trying.
If that does not work, the next step is buy another keyboard, if you think it is worth gambling the money, as there is no guarantee this will cure the problem, although it is the most likely cause.
Check ebay and Amazon for new or used. Here in the UK a new laptop k/b can be found for around £15 up.
Please advise back on progress.
Good Luck - Keep us posted.