Even if you remove the software from the computer, in IE it will still let babylon search as the default site for new tabs in the browser.
I don't know if it is possible to find it in any menu in IE (at least I didn't), but you can change it in the windows registry.
Open a dos shell, or execute "RegEdit" through the launch menu.
Find the key:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\About URLs\Tabs
and change the entry that points to babylon search, to the one you desire (be it google, bing, or whatever).
I hope that helps
and in value data fill this "res://ieframe.dll/tabswelcome.htm" without quotes...enjoy