Why has my trackpad started to behave erratically again?

ASUS model: X555LA-XX290H

Intel Core i3-4010U

Windows 10 Home 64-bit

When I first bought my laptop a couple of years ago I upgraded to Windows 10 a few days afterwards. The trackpad would never scroll properly from then on - there was a huge amount of input lag whenever I tried to scroll.

I mostly used a mouse, but after a year or so the trackpad started to work normally. There was one period of a few days where it stop scrolling again, but other than that it's been fine.

However, a couple of days ago it stopped scrolling properly again. The following day the cursor started jumping around simply from keeping my finger on the trackpad - without moving my finger at all.

I've got the most recent driver installed (which hasn't been updated for some time), repaired the program, reinstalled it and checked for viruses but nothing has worked.

When the program - ASUS Smart Gesture - was uninstalled (and before I reinstalled it), the trackpad was still behaving erratically.

Any help would be appreciated.

Thanks