Click Start >>click on search and the type in device manager.
you will see an icon device manager click on it.
Now click on keyboard and input device highlight the keyboard driver and hit delete key on the keyboard let it be removed use the mouse to shut the computer down, after a minuite turn the power on and once the windows load it will load the keyboard driver and it will be fixed. If you find the same problem then its the keyboard which needs to be changed.
we are identifying the hardware as well as software problem.
If sofware issue the it will be fixed as you follow the steps i a gave and if not then the keyboard has to be changed.
Let me know if you have any question.
if you are facing difficulty to follow step i can offer you a remote support through which i will be able to see and control your screen and will fix the problem in front of you.
And if the computer is under one year i would suggest you to get the keyboard replaced.