All of my browsers have been hijacked by sometrhing called "proxy.allsearchapp.com". The program has installed itself as the default start page and default search engine in all of my browsers. It blocks browsers' setup options, so I am cannot change the start page or default search engine through the browsers. I have IE, Chrome and Firefox. All are infected. I am running Windows 7. Any ideas on how I can get rid of this would be most appreciated..