keypad don't match up

hello, our Inspiron 4000 PIII, 1000ghz, 256ram, 10hd, window XP-p2  home ex....the letters don't match up, like when i typed the letter i instead it's 5, and the alphabet jklm is like 1230, o p is 6-, and u is 4, it seems like letters don't match up the keys, if anyone might have idea how to fix this problem, appreciate your help...thax