Having problems with Omiga-plus.com Virus

All my browsers have been hijacked by the isearch.omiga-plus.com search engine, which has taken over my browser homepage and search engines too. I have resorted to Google to help me solve this problem but I cannot seem to get an answer. I have cleared the history, homepage settings and even deleted one of the omiga files in regedit but nothing seems to work. Please help me solve this.
