Click the wrench and go to "Options". Click on the "Manage Search Engines" on the Basics tab, delete the WhiteSmoke search engine, and set your default search engine to your choice.
On the search engine line of the Google Chrome next to the star there should be a little blue square with the letters ws right click on it and click on uninstall. It will go away. It will be next to the Goggle wrench.
This appears to be a very tenacious bit of spyware/malware. If all of the advice given about doesn't solve the problem you could have a look at using the Microsoft Malicious Software Removal Tool from here.