my macbook keyboard has started behaving very erratically, it drags items without clicking on them, sometimes when typing, the icon jumps so i end up typing in the middle of a word ive already typed, it selects items randomly,

ive done a full restore which didnt help, and downloaded clamXav to see if there was a bug, but nothing,

ive done a PRAM and SMC reset and ran the hardware test but nothing showed up

please note im not to computer/mac literate!!!!

any help please