Hi,
1. Which operating system are you using?
2. Are you able to use any other USB devices?
3. Did you try connecting it to different USB port?
4. What is the status of the mouse on device manager?
Step 1: Run the fix it tool from the following article and check.
Hardware devices are not working or are not detected in Windowshttp://support.microsoft.com/mats/hardware_device_problems/
Step 2: Update the mouse drivers.