How to fix Quicktime that is not playing videos from Apple's website? I have a windows 7 system and would like to watch one of Apple's keynotes.

I have downloaded Quicktime player version 7.0 and it automatically starts as soon as I click on the video. But after starting nothing seems to be happening. I just see a Quicktime loading screen and that is it. No video seen.
I have problems playing any Quicktime video for that matter especially from the Apple website.

What could be going wrong and how to fix?
In the past I had ad blockers that picked up on Apple's website videos (not the keynote that you have mentioned specifically) but worth checking if you have any extensions or addons installed that is currently doing that