Microsoft Vista search window keeps opening

I recently got a new Dell laptop with Vista as operating system , but since the last couple of days whenever i open internet explorer a small search window opens , the one which pops up ctrl f

at times the windows explorer search winddow opens , if i try to close it it opens up again . Any time i do any meaningful work , the focus shifts to the search window causing me much grief. Does any one know whats happening and how to fix this