Tablet Touch Screen partially unresponsive
I know this is a low tech answer but I've had this happen before, normally due to screen smudge from fingers or liquid splash/residue on the screen.
Give the screen a good clean (use cloth from a pair of glasses) and see if the problem persists.  Failing that, shutdown, remove the battery, and leave it for 5 minutes just in case it's a charge/capacitance issue.