Homepage Hijacked by Internet Security?

Answer 1

This is kind of a vague question, so all I can suggest is downloading Spybot: Search and Destroy, installing it, updating it, and running its scan tool. There's also another tool built into it that lets you make sure homepages don't get hijacked. Just correct the problem with that and it might work.
Link: http://www.safer-networking.org/

Otherwise you'll have to get advanced and use a tool such as "Hijack This" to remove the object causing the problem.

Answer 2

No, you have a hijacker. Get Spybot or Superantispyware to remove that hijacker.