Laptop Questions? Ask a Laptop Technician for Answers ASAP!
If a factory reset and software updates did not help, then the tablet itself has a hardware fault.
If you haven't already done so, try wiping the touchscreen with a damp cloth, in case it is contaminated with dirt and getting confused.
If that doesn't work then there isn't anything that can be done to fix this, except a costly repair which would cost more than the price of a new tablet.