have a dell vostro 1520, installed an external usb keyboard which works fine but the laptop's keyboard does not work properly.

in the log in screen everything works as it should, once logged in the keyboard breaks. keys that have an alternate symbol accessible with the FN key render it by default. Meaning i have to press the FN key for it to render the proper ones- p has the * as FN, in order to get the p i have to press p+FN.