Hi, Could you say something more about the yahoo hijack. I never heard . But may be you are affected with redirect virus. If you are specific or enclose a screenshot, then useful solution could be given. There are many programs, but like malware bytes, these do not show, what they are doing and you are running the risk of more trouble, if you do not know which item to be deleted and what not.
Please a little explanation of how your browser is affected may be helpful