So you are using a non-standard layout then? You should still be able to try the following and see if it helps resolve the problem. Note: If you changed the layout yourself, you may have to change it again once this is done.
1. Uninstall the keyboard driver.
2. Reboot the computer (without reinstalling the driver).
3. When it restarts, it should reinstall the driver on its own.
If this doesn't work, you may wish to try connecting/reconnecting an external keyboard and see if it works fine. If it does, then it could be the keys themselves that are the issue.
You may also want to try updating the Synaptics Driver if the above doesn't help.