Some keys not working

[klgupta]

some keys like v,b,z, not working

 

[szaboaz]

How did this happen? Yesterday everything was okay, and today they aren't working? Maybe some dirt got under the keys, or something was spilt. Solution: cleaning, NOT UNDER THE TAP (I've tried to clean a keyboard once, I took it apart, and found some dirt on the plastic sheets, so I washed them. It never worked after that. )