You should actually do this every year. Even more often if you spend a lot of time on the computer. This is recommended by Kim Komando (the computer guru) in one of her recent emails. I was shocked to see how well this works, and how far off mine was!
To re-calibrate your mouse, click and hold on the capital G below, then drag it toward the small g.
If it doesn't work immediately, you might want to clean your mouse, as the calibration is off.
Good lord!! You'll believe anything
I'M SURE YOU WILL ALSO RECOMMEND THIS TO ALL YOUR FRIENDS ONCE YOU SEE HOW MUCH SMOOTHER AND BETTER THE MOUSE WORKS AFTER BEING CALIBRATED! AMAZING!