go tour you nvidia control panel and uncheck the enable desktop manager. even if your running 2 moniters you dont need it, its kinda buggy. if you see a rundll.exe in your task manager you know its still on. it also, resets your menu reaction delay, if you changed it, couple bugs i guess
right click on your desktop, click the tab for apparence and disable
it with the effects button. then right click on my computer click the advanced tab go to performance settings, in the tab for visual effects theres a smooth scroll setting among many other visual effects.
might be an issue with your mouse driver, I have the same problem wiht my synaptics touchpad drivers installed. updating drivers prob won't help, try uninstalling your mouse both drivers and through device manager and see if that helps. but even if that's the cause I won't know how to make your old mouse software work... I'm stuck with it as well.
oh, you can use opera, enable smooth scrolling through the ini file and this will never happen