I can't get my keyboard to type any character on

If you are lucky it is just a stuck key. Turn it upside down and spank it on the bottom. Then try it again. The keys can just stick by typing on them and hitting them at an angle or be caused by mechanical wear or a foreign substance ie dirt or spilled liquids.

It is also possible you have a keyboard failure or even a issue with the main board. The keyboard can be replaced for $100 plus labor but eh motherboard can cost as much as a new laptop.