Mouse wheel sensibility problem

[Elphizo]

Hi everyone. I have an annoying problem with my mouse. Sometimes the wheel is too much sensible. For example, in firefox, if I roll the wheel a bit it scroll the page directly to the bottom. This happens randomly when I boot the system, and it persist during the entire session. I can't find a way to set up the wheel sensibility. I have Hardy(but I had the same problem under gutsy). The mouse is a Microsoft wireless laser mouse 5000, and I managed to enable all five buttons, but I haven't found anything about this problem in internet.
Can anyone help me, please?

Sorry for my english, and thanks for reading!

[nilarimogard]

I think that happens if you boot into windows and then restart and boot into ubuntu. You can either: shut down and then boot into ubuntu, or unplug and then plug back in your mouse.