I am running Windows 7 Home Premium x64, Service Pack 1.
My mouse is a Logitech MX620 Cordless Laser Mouse, driver provided by Logitech: Logitech HID-compliant Cordless Mouse, version 188.8.131.52 (8/24/2010). SetPoint control center is version 6.20.60, driver version 5.20.51.
Now that the technical details are out of the way, here is my story: my computer came with Vista x86, and everything worked fine. I bought the OEM Windows install listed above and did a fresh install on a blank hard drive (i.e. not an upgrade.)
Now my mouse wheel is acting wonky. It scrolls just fine for the most part, but is super-sensitive when it comes to scrolling a tiny fraction, such as when I press it to use it as a middle button. Same hardware as with Vista, but obviously different OS and drivers (using x64 SetPoint and drivers, updated versions).
Again, it scrolls normally, it is just super-sensitive when moving it a tiny bit. If I go to middle-click to open a link in a new tab, the mouse will scroll the link out from underneath my cursor. If I scroll to the top of a page to click a navigation link, it might scroll back down one unit.
When I google or search StackExchange for help, everything comes up with "my mouse doesn't scroll" or "it scrolls too little/too far." My problem is it scrolls fine for normal scrolling, but if I touch the wheel a tiny bit, it will scroll when I don't think it should (and it didn't under Vista).
One other note -- I do have a "microgear" switch under the mouse that makes it "click" when I scroll, but that doesn't affect my problem. The amount of the wheel movement that is undesired is under the "gear threshold" or whatever of the mouse.
Essentially, I want to have a threshold where if I move the mouse wheel less than that amount, it does nothing. This is apparently how Vista handled it, but Windows 7 does not.