Mouse Scroll Wheel Inverted

So I've been using an HP USB mouse for quite some time. Not too long ago, the scroll wheel started getting all jumpy and scrolling erratically.

I decided to use a new mouse. This one is a generic brand PS2 mouse. The scroll wheel works, aside from one small problem... the scrolling is inverted! When I'm on a web page or in Notepad, I have to scroll the wheel up to make the page scroll down.

I figured, no problem, there's probably an option to switch that. Well I booted up the mouse options from control panel, and no such luck. Any ideas on how to fix this? The mouse was plug-and-play so Vista just assigned it a generic driver.