Bad drivers, or interference with the wireless connection. What’s your OS?

Actually google for drivers with your mouse brand and model and your OS, and try them out

I believe it’s windows XP. I don’t know if it’s the scroll wheel that has a weird spot(s) or it gets stuck between detents and doesn’t know where to stay. So I usually end up pressing it once to make it do that auto scroll thing instead of manually rolling it. Probably my eye- brain connection loosing it’s place when everything jumps a notch. Old dude stuff.
The jumps are quite large each time I roll the wheel one click.

Ah, you have to go to the controll panel, and adjsut the scrolling speed, it’s probably a default setting for the mouse, try lowering the scroll to like, 2 lines or whatever its lsited as in xp and see if it helps.