Pat, thanks for taking an interest in my issue. My display adapters listed in Device Manager are:
Intel HD Graphics Family - AMD v.8.882.2.3000
Radeon HD 7470M - AMD v.8.882.2.3000
This problem began about 2 months ago and prior to that all worked fine. I can also tell you that some video clips, like what is found on U-Tube, play fine with video displayed. So I am quite dumbfounded.
Your Radeon driver is way out of date; I recommend that you install the latest driver from the AMD website.
Your Intel card lists an AMD driver; I don't think that can work at all. I suggest that you install the latest Intel driver.
Create a System Restore Point before you update the drivers - just in case something goes wrong.