Playing Video on a Windows 7 Laptop

I recently ran a driver detective program to try to regain the ability to play videos on my Laptop. It worked and all was ok till today when I installed a large windows update.
Now when I bring up a web page that should play me a video I just get a white square but no sign of a video and nothing to indicate why not. Running the Driver Detective program shows me no hints.
I tested the site on my older PC with Home Vista and the video plays on that.
How can I test to find what is needed, and then update or install it?
It must be a common problem so I’m hoping for a simple reply!
Thanks, John, York, UK