The keys on my keyboard will not type :(?

Okay Im socomputer illiterate so not sure how to word this but I hae a Dell Inspiron 1501 laptop that Im on now. It was working great ut now when I type, it will not pick up every key that I hit. It looks like I have a ton of different typos and after wriing sentence or a paragaph, I have to go back thru and edit almost every word that is missing letters. I did a driver update. I scanned for viruses, spam, etc., then I made sure the keys are clean. Its aggravating. I have just had to edit everything Ive typed so far. I am going to type the following sentence and not edit it so you can see what I mean: Im typing nrmally and as I type you will sethat the keybard is skppingthe keys I am strking includnwhn I hit the spacbar!!! Ggrrr. Any suggestins?