You need to determine if you have a hardware or software problem.
Please try the following command:
click on start and type osk -- this should start the "Onscreen Keyboard" where you can click on the screen to type. If you have no problems with OSK then you will need to replace the keyboard.
You could also test with an external USB keyboard.
Laptop keyboards can be replaced if you have the manual to show you how. Replacement keyboard can often be found on Ebay.