I cannot get Firefox to retain my homepage after following the correct procedure.

I have used the same homepage for several years. Now, all of a sudden, <www.searchqu.com/406> seems to have highjacked my homepage. I cannot get rid of it. I have gone through the procedure of going to Tools/Options/etc., to reset my homepage to my chosen one. I have clicked OK, opened new tabs, clicked on the homepage symbol and everything appears to be OK, however the next time I open Firefox, www.searchqu.com/406 appears as my homepage. I would like to remove/uninstall/delete or otherwise get rid of www.searchqu.com/406 altogether or at least hide it from Firefox's view. Any help ??