Update,
I transferred the account over to Outlook and ALL URLs open as expected. I then sent the WM account an email with a YT link. Chrome opened and went to YT but was just a blank white screen, however the sound was playing without issue. The same link from Outlook worked fine. I have tried holding CTRL down to no avail. (thanks Giggz). I have tried the M$ Fixit repair but that has failed. Default programmes is set correctly. IN associations I have set .htm .html and .url to Chrome but still no joy. Thank you