The problem is simply from the mouse wheel itself, and here is a 2-minutes quick fix for you and eventually you will become a mouse Technician. This solution is only for a wheel mouse and not an optical mouse.
Causes of Mouse Problems
When your mouse starts misbehaving, the problem is from only one part of the hardware, "the wheel" which would be the troubleshooting center. Its either the roller of the wheel is dirty, damaged or misplaced.
The mouse could have dropped on the floor or you've been using it without a pad thereby packing dirt into the wheel house and its rollers.
Solution
Capsize your mouse so that the wheel is exposed and use you fingers to twist to the direction of the arrow around the wheel, when done look inside you will see 1 projected wheel with a rim and 2 other flat rollers on the right and the top, just check that they are in proper position.
See diagram below to know how it's supposed to be:
When in position.
What you will do is to simply look for a sharp object like a key or screw driver, after this you will see some dirt around the wheel rollers; so remove all the dirt properly from the 3 rollers and blow the dirt away. After this your mouse will work perfectly.
It always happen like this, see the diagram above then try to put it in place and also make sure its free of dirt.
When you have trouble-shooted the mouse wheel rollers close it back by turning the cover around the wheel in the opposite direction. Check the connector of the mouse behind the computer and remove it and blow it with your mouth and connect it back to its position. Look for a good mouse pad and put it under the mouse, start using it immediately!
People will now start consulting you to help them work on their mouse and eventually you've become a mouse Techie.
