keyboard not working.work only if you press hard?

It can be debrits under the keys, or a worn out keyboard that's telling you that it need to be replacded.

First step is to make sure that there are no debrits.
Hold the keyboard side way and gently tap it's side.
If debrits fall and it works beter, this was the cause.

If there are no debrits falling, then, it's probably getting to old.

Don't eat over or near the keyboard.

Electro
January 2016

This will very probably be a keyboard on an unspecified laptop - when it has happened to me in the past it has not been on all keys - just a few of them - the cause has always been food debris trapped under the key caps - mostly crumbs from cheese rolls.

The solution is to remove the food debris - begin with a vacuum cleaner but place a cloth over the nozzle to catch any bits of keyboard that come lose - in extreme cases lift the key cap and clean with a dusting brush.

Good Luck...
January 2016

Keyboard - - - - - - - - in what?

Probably keyboard just needs replacing.

XXX
January 2016