Suspect keyboard virus/malware, toshiba lap

ran full system scan plus norton power eraser. has not fixed a virus or malware that makes laptop keyboard mistype.  affects alpha numeric function of keyboard. for example, backspace displays: wpf, key p displays: pf (with multiple spaces after), etc.  the a key displays: a (plus a hard return before and after).  some keys seem to be unaffected.  the alpha numeric function of my laptop works fine with an external wireless keyboard.  suspect malware/virus.  other people have posted similar problems with toshiba computers using norton security software (on online forums).  please is there something i can download? help!