My down and right arrow isnt working.?

they were working earlier today then they were being a little weird i.e i would have to tap it over and over to scroll down instead of just holding it. then i tried moving the line to edit a word and it wasn't working. so i looked it up and found that i had to clean it. so i popped em open and cleaned them out. put them back is and now they arent working. my keyboard driver is up to date. anyone know how i could fix this? it will be much much appreciated. thank you