some keys on key brod dont work?

Those are the keys that are used the most under normal use.

Check that they travel freely. There may be some debrits stuck under them.
Try removing and cleaning the problem keys.
If you can't remove them, try using some compressed air.

If they do travel freely, my guess would be that they are worn out. If that's the case, your only option is to replace the keyboard.

Electro
July 2013