Sorry don't know the answer just somethings to check.
It could be a virus, but it doesn't seem the most likely cause, you will have to run your anti-virus to be sure.
I would of said that the battery on your wireless keyboard needed replacing if it wasn't for the fact that it is happening on your laptop keyboard as well, but it is still worth checking as your laptop may be affected by your wireless keyboard - unlikely but.
You could have a stuck key (either on your laptop or on your wireless keyboard).
Have you moved something, IE the base station for the wireless keyboard - out of range?
Are you using a nonstandard font - it could be the one you are using is corrupt?