Annie, it could just be that yahoo choked and your reboot may have cured it.

In Tools > IE Options > Advanced > Browsing > uncheck install on demand IE and other. That should cause IE to ignore what the site thinks you need to view it.

I'm using Zone Alarmn 6 now, and I know when I have ad blocking or mobile control settings to high in ZA, surfing is a pita on some sites, because they just don't want to function at all unless you give them carte blanche to control your viewing. I refuse to go to those sites.

I would give yahoo another try though. You never know.