Now, my mouse cursor moves like 1px for every 1/4 inch I move the mouse. If I move the mouse fast, it responds ok. (haven't even launched IE after upgrading it btw)
It's an Intellimouse Optical USB (5btn) from back in the day, aka WX mouse

I have a PS/2 adapter that I've been using since.
I couldn't find anything helpful on the ole googs!
Also, the mouse wheel doesn't work now. Way to go Microsoft!

I tried updating the drivers, but no go. Will try removing the adapter & see what happens....
