Has the change given you a new "Home" page ?
If so, and you're referring to, say, the Google toolbar's spellcheck and Autofill features, then just go to Google, then Tools/Internet Options, and re-select Google as your Home page.
If the toolbar doesn't re-appear, right click somewhere at the top by the browser buttons and ensure Google is ticked. If it doesn't appear as an option, you might have to download it again.
If you're not wanting Google's toolbar or use a browser other than IE6, post back.