To change the number of lines that you scroll
Open Mouse in Control Panel.
On the Wheel tab, under Scrolling, click Scroll, and then select the number of lines to scroll with each notch on the wheel.
Click Scroll one "screen" at a time.
To open Mouse, click Start, click Control Panel, click Printers and Other Hardware, and then click Mouse.
A "screen" is different depending on the size of your window and the program you are using. Scrolling one screen at a time is equivalent to using the PAGE UP or PAGE DOWN keys on your keyboard, or to clicking above or below the scroll bar.
Some programs may limit the maximum number of lines that you can scroll with each notch of the wheel.
If your mouse does not have a mouse wheel, the Wheel tab may not appear.