Keyboard button combinations not working

I had recently bought an aspire 5516 notebook vista laptop. Everything was fine until I went to go play my games. I had noticed that certain key combination such as a, d, and c did not work, nor' up, left, shift, and z.
Though it's really just z and up/let or down/right that're the problems.

Is there anything I can do to get the laptop to accept the key combinations?

I had still tried numerous google searches, however, I could not find any specific methods to allow my keyboard such combinations.

Does this mean there is no way to allow such things through a configuration?
Or does it even mean I would have to replace the keyboard?

I'd really need to know if there is a method to allow the key combinations, otherwise I cannot play touhou for squat.
Any response would be good, actually.