Depending on where your mouse is plugged in it may cause erratic behavior. Though if you were able to use it in the same environment prior without any problems, then this is less likely the cause. Please plug it directly into the back of the computer for the most effective connection.
Using a KVM switch, docking station, or USB hub can cause conflicts.
Also, certain programs are also known to cause issues with the mouse such as VMWare or Paradox.
Lastly, other software drivers can sometimes cause issues. Specifically, drivers for other pointing devices. If you had any other devices that you were using, make sure that the software has been fully uninstalled.