She has a wired HP optical mouse. It plugs into the normal mouse port, not USB.

I tried scrolling with Internet Explorer, Adobe Reader, Notepad, Itunes, and the standard windows window (like, looking at program files). It had a problem with all of them except Itunes. Something interesting found out: I noticed that it seems to have more problems when there is more information display at any one given time. For example, when I was looking at program files, I reduced the window to show only a few icons in a single row. When I did this, the scrolling was normal and smooth like it would be on my own computer.

1. Uninstall the mouse through Device Manager. Restart computer, and it'll be reinstalled.

2. Run defrag.

3. Try another mouse.

Problem Solved