I have Diablo III, and it's working just fine. You may try
1. uninstall the present, from the Steelseries folder in Start Menu,
2. look for latest update, and install that.
It may be a matter of some "attached third party software" you have installed. Like many programs come with various toolbars, and if you're not paying attention you get something new... and you don't really know where it came from.
Be careful with installations, so you don't install "extras".