It seems you have found the answer for you original question you asked by yourself as you wrote that the website you are trying to visit does not support IE9 anymore.
I guess you have posted this question in the Vista forum because IE9 is the latest version of Internet Explorer that will run on Vista.
If I am using Vista and I want to visit websites which are no longer supported by IE9 I prefer to use the latest Firefox browser, which works very well for me.
If I want to visit websites that use Flash I will also install the Flash player (for Firefox only).
If you have problems installing other browsers on Vista or XP I think it is best to post a new question about that specific problem and not use the same thread, because the Original question you asked is already answered! (by yourself).