Make sure the Tractivity Bluetooth USB adaptor is inserted into the computer correctly. If inserted correctly it will glow blue. Make sure your Sensor is awake by shaking it for a few seconds. Note: The Sensor will automatically go to sleep to save battery power after a few minutes. And the Sensor needs to be close to the computer that has your Tractivity Bluetooth USB adaptor plugged into it (within 6 feet (2 metres), but not closer than 1 inch (2 cm)). If you are still having trouble, remove the battery from the Sensor for five seconds and try again. Lastly, if the Sensor is more than a year old, the original battery might need replacing. Replace the battery with a standard CR2032 coin cell battery.