Note that many websites have their own advertising, unrelated to adware.
Accepting their "second opinion when you surf" actually gives you a toolbar named "Mysearch". 2nd-thought will redirect your searches as long as it is installed on your computer.
Browswer hijacker that will reset your home page and often redirect your searches to porn sites. Sometimes it will prevent you from changing your home page.
Kill this process - stcloader.exe
Delete the file stcloader.exe