Why does my computer screen jump?

[golflogo]

Screen jumps around. For instance, when deleting an email, 3 or 4 messages will also be deleted.

 

[ksiemb]

Screen jumps around. For instance, when deleting an email, 3 or 4 messages will also be deleted.

pc - laptop - mouse - touchscreen ?

 

[golflogo]

pc - laptop - mouse - touchscreen ?

Dell PC. When I use the page up or page down, it resets itself to previous screen, before finally settling down,(for lack of a better description).