Got a new HP? I've seen this on three client laptops in the last week.
IIRC, the option to show this Yahoo search bar is in the new, repellent
HP "PC Health" suite of cr*p. Look around carefully - I actually gave up
on the first computer but found it on the second one. I'm sorry but I
dont remember exactly where the option to turn it off is but it is most
definitely there.