It is a browser hijacker. Google "Hijack This!", a programme that detects browser hijackers, and allows you to remove them. However, if you are not very experienced with computers it's easy to make a mistake with Hijack This, so you might want to get a friend to help you. Anyway, d/l Hijack This, run it (click on Scan), and search the results you get for any reference to Search Assistant or SearchWeb2. If you find them, check the box for removal and proceed. *Important* -- make sure to leave alone any "Search" references you find that also reference Google or any other established program.

I use this terrific utility once a month, or when I see that my browser is not doing what I want it to (especially searches).