The Internet Explorer listing in the Windows Components section actually only enabled/disables the default shortcuts on your desktop and in your Start doesn't control whether or not IE is installed. (That's why the reported file size is 0.0MB despite the fact that Internet Explorer is around 15MB in size.)

That said, when you install Internet Explorer 7 it will replace cannot run them side-by-side and switch back and forth. However, you can return to IE6 at any time by uninstalling IE7, which will restore the former from backup.

Hope this helps,