Help with quicktime

I've recently downloaded the newest Quicktime, and have noticed that on websites, it won't work. Any images are replaced by a "Q?" And only 2 videos I know work on it. This happens on both IE and Firefox. I've tried downloading older versions, and the sae thing happens, but the "Q?" is replaced with a torn film reel symbol. I can get Macromedia 7 working, and I've been using that for a while, but I'd like to get quicktime working. Another thing odd is that it plays most downloaded movies, but just not on websites. Can anybody help? Thanks

You could try fully uninstalling Quicktime as described HERE (http://forum.worldstart.com/printthread.php?t=65812) ,then reinstalling it.

Check that the quicktime plugins are installed in the IE and firefox plugin folders.