The Logitech TrackMan Marble gives you superior comfort – for either hand. Ambidextrous design provides long-lasting comfort for right- and left-handed people. Convenient button controls let you easily move forward and backward when you're surfing the Web. Click the large buttons together and use the ball for auto-scrolling. Fingertip-based control enables fast, accurate cursor movements. Patented Marble optical technology ensures smooth tracking. Clean the button/key with compressed air. Verify the product or receiver is connected directly to the computer and not to a hub, extender, switch or something similar. Unpair/repair or disconnect/reconnect hardware. Upgrade firmware if available. Windows only — try a different USB port. If it makes a difference, try updating the motherboard USB chipset driver. Try on a different computer. Windows only — if it works on a different computer, then the issue might be related to a USB chipset driver. If you're not sure if the problem is a hardware or software issue, try switching the buttons in the settings (left click becomes right click and right click becomes left click). If the problem moves to the new button it is a software setting or application issue and hardware troubleshooting cannot resolve it. If the problem stays with the same button it is a hardware issue.If a single-click always double-clicks, check the settings (Windows mouse settings and/or in Logitech SetPoint/Options/G HUB/Control Center/Gaming Software) to verify if the button is set to Single Click is Double Click. NOTE: If buttons or keys respond incorrectly in a particular program, verify if the problem is specific to the software by testing in other programs.