Well, it should be possible to remove IE 6 but you are still gonna be stuck with an older version of IE since its integrated into the OS. So if you just want to get rid of IE 6 and use an older version you gotta go into add remove programs (or add remove windows components) and uninstall it.
Otherwise to use Opera just install it and use it instead of IE since there really is no getting rid of it.
Otherwise to use Opera just install it and use it instead of IE since there really is no getting rid of it.