How to Remove Search Function from header?

It isn’t in any widget (I checked several times), but the search window is in my header, and it is messing up my header image, taking up half of the header image space. Really weird! How do I remove this?

And how do I get the header image to take up the entire space? The theme automatically shrinks it down to half of its original size, even though there is more space in the header area…

Please help if you can. Thanks!

http://www.hannahmazing.com/