Clean the scroll wheel with compressed air
Remove dirt and debris around the wheel
Restart your computer
Unplug and reconnect the mouse
Try a different USB port
Replace the mouse battery if it is wireless
Test the mouse on another computer
Update or reinstall mouse drivers
Check mouse settings in the operating system
Disable and re-enable the mouse device
Update the operating system
Check for software conflicts
Open the mouse and clean the internal encoder
Replace the mouse if the wheel is physically damaged