Typing repeating a letter across the screen

Hello,

I have a laptop with windows 7. Oftentimes, when I type it will start repeating a letter across the screen (most frequently, b's or h's, but other letters as well, like this:

bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

Can you tell me how to get it to stop this?

My e-mail address is ***@***.

Thanks,

Oscar Overcash