Please note that this answer is more of a workaround than a direct solution. See my other answer for a suggested direct solution (It basically says "Try rebooting", though).
Since you're on the stock launcher (Which, if I recall correctly, doesn't allow you to remove that search bar), the best answer I can think of is to try installing an alternative launcher. I personally use Nova Launcher (The $4 "Prime" version actually).
After installing the new launcher, most (Nova included) will give you an option to import your old icon layout if you want to. But by default, you're basically given a clean slate.
I usually recommend Nova because it nearly mimics the default launcher (no crazy features or surprises) and adds a few nice features - my favorite is that it has an "Uninstall" drag-area that lets you uninstall an app without going to its settings/info page.
Other alternatives that I've played with include...
Go Launcher, [Free, optional $6 upgrade] supports countless themes and skins, but has a somewhat different look and behavior compared to stock.
ADW Launcher, [Free, optional $3 upgrade] one of the most mature custom launchers available. It is closer to the standard launcher than Go is, and supports a huge number of themes, icon packs, etc.
Next Launcher, [Free Trial, full app is $16!] a very different launcher with 3D effects and such. The full version is pretty expensive, but I guess it would be fun to show off to friends and such (I don't know how user-friendly it actually is).
Espier Launcher [Free, $8 upgrade for the new iOS style] is a launcher that tries to mimic iOS's Springboard, and succeeds to a surprising extent.