Why is my mouse cursor not working?

My mouse and keyboard are part of a set I got from Dell when I purchased my desktop computer. Until a couple months ago my mouse was working great. Then it started jumping all over the screen and pages I’m on will continue scrolling even after I stop rolling the wheel on the mouse. I’ve done everything from moving the USB connection to a different port, restarting the computer, turning the mouse on and off, use a different mouse pad, use no mouse pad, and today I took the mouse apart to clean it. I don’t know where to find the serial number and none of the pictures on this site show my mouse and keyboard set. I’ve had these for three years now.