If the site is search.yahoo.com/firefox, I just went there with IE9 in Vista Business and it showed up just fine. I checked it and can find no problems of any sort. I'm not sure why you're having trouble across the board with it.
I recommend following Shadow's advice. It really isn't as hard as it looks for a Skilled member. Perhaps if you explain the parts you don't understand, we can provide more detailed instructions. Ah, as I was typing, Shadow did most of it for you.
We're not certain the cause (and I don't have the problem so it probably isn't the webpage), so there's no easy fix. As it happens to all browsers, it doesn't have anything to do with those specific programs - so we need to look at the connection itself. Resetting it is what Shadow's recommendations will do - no guarantees, but it's the best place to start given the problem as you've presented it.
I hope this helps.
Good luck!