It sounds like you have turned on the "NumLock" feature that many laptops have.( j=1 k=2 l=3 u=4 i=5 o=6 m=0) It's intended for use by people who need to enter large amounts of numeric data.
Find the NumLock key and press it to reverse things and set it back to normal. On my Dell it's Fn + F4, on my Compaq it's Fn + ScrLk. It's different on every make and model. But, it's somewhere on the keyboard .
Good Luck! :)