HP Compaq Presario,Presario 800AP Supplementary Manual page 33

Edge Motion allows you to continue to scroll once your finger
reaches the edge of the TouchPad. When this feature is turned
on, the window continues to scroll until you lift your finger.
To turn on Edge Motion, complete the following steps:
1. From the Windows desktop, click Start, point to Settings,
and then click Control Panel.
2. Double-click the Mouse icon.
3. Click the Edge Motion tab.
4. Select When Dragging, Always, and When Scrolling to
turn on Edge Motion.
5. Click OK to accept the changes and close the dialog box.