The circle that appears on the screen when using the erase and paint tool disappears. It only resets when I reboot my PC. Thanks.
Check to be sure your caps lock isn't on, first of all.
Could you please go to the preferences of the editor (Edit>Preferences) and under 'Preformance' section increase the ram usage (Donot make it 100 %, try to keep is around 90 %)
Relaunch PSE and check is there any change in the performance after this.