Are Photoshop and OS fully updated and have you performed the usual trouble-shooting routines (trashing prefs by keeping command-alt-shift/ctrl-alt-shift pressed while starting Photoshop after making sure all customized presets like Actions, Patterns, Brushes etc. have been saved and making a note of the Preferences you’ve changed, 3rd party plug-ins deactivation, system maintenance, cleaning caches, font validation, etc.)?
Are you sure typing on the keyboard isn't activating the mouse pad because your fingers/thumbs are close? Some are too sensitive...
I tried trashing the settings, that didn't work. I reset the character, that didn't either.
It was a fresh install so there are no third party plugins, actions or brushes - nor had I changed any settings.
My computer is up to date, as is the software.
What do you mean by system maintenance and how do I clean the cache?
None of the stuff there - at least the steps that can be done in Windows - appear to have helped :/