Loss of 'Internet Options' tool in Internet Explorer

> For an unknown reason, I've suddenly lost access to
> my 'Internet Options' tool in Microsoft Internet Explorer.
>
> When I try access it, I get a pop-up messages that
> reads: "This operation has been cancelled due to
> restrictions in effect on this computer. Please contact
> your system administrator." I'm the only user, so I've
> always had full admin rights.
>
> I've tried reinstalling IE6, but that didn't solve the
> problem.
>
> I'm a broadband subscriber using Comcast cable connect. I
> don't know if this means anything either, but according to
> the top line of my IE screen, "I'm now using Microsoft
> Internet Explorer provided by Comcast High-Speed
> Internet." Maybe I'm going nuts, but I don't remember
> seeing that before.
>
> Any help or suggestions will be appreciated.