Laptop keyboarD

Turn it off then on. See if that helps.

Click on start, right click My Computer or computer on vista systems, select properties, select the hardware tab, select device manager. Select keyboards, right click the keyboard, select to uninstall it. Select Action, Select scan for hardware changes. It should find the keyboard and reinstall it.
See if that helps

Turn the laptop off, remove the battery. Remove any screws in where the battery was. There may be none, two or three screws, depending on the model.
Open the laptop all the way pushing the monitor back as far as it goes.
Next you will pry up the plastic piece the power button is connected to. On the right or left side of the plastic piece should be a notch that looks like you could insert a small flat blade screw driver in, that's what it's for. Carefully pry up and wiggle the long plastic piece free. The keyboard is connected by two or three screws at the top. Remove them. Slide the keyboard toward the monitor and it should come free. See and remember how the keyboard is connected. Remove it's cable from the laptop then reconnect it. Put it all back together in reverse order. See if that helps.

If that doesn't help then you need a new keyboard. If a new keyboard doesn't solve the problem, the motherboard needs replacement.