HP EliteOne 800 G1 Maintenance & Service Manual page 158

Mouse does not respond to movement or is too slow.
Cause
Mouse may need cleaning.
Mouse may need repair.
Computer is in Sleep state.
Mouse will only move vertically, horizontally, or movement is jerky.
Cause
Mouse roller ball or the rotating encoder shafts that make
contact with the ball are dirty.
148 Chapter 8 Troubleshooting without diagnostics
Solution
Remove the roller ball cover on the mouse and clean the
internal components.
See the Worldwide Limited Warranty for terms and
conditions.
Press the power button to resume from Sleep state.
CAUTION: When attempting to resume from Sleep state,
do not hold down the power button for more than four
seconds. Otherwise, the computer will shut down and you will
lose any unsaved data.
Solution
Remove roller ball cover from the bottom of the mouse and
clean the internal components with a mouse cleaning kit
available from most computer stores.