Why won’t Windows Live Mail open Compose when clicking email link?

I have been happily using Windows Live Mail with Gmail and Hotmail accounts for a couple of years. However, now I can't launch the Compose screen from an email hyperlink on the internet or in emails I receive. If I click an email address on a website, nothing happens at all. If I click an email address within an email that I've received, it opens the browser, not the Compose screen. It seems Live Mail isn't launching from hyperlinks. It means I have to cut and paste the email addresses, quite frustrating. 

Everything else is working fine, I can click website links in emails and on websites and get connected. I can send, receive, compose from the client - just won't launch from email hyperlinks.

Things worth knowing:

The problem is with both Gmail and Hotmail

It's the same problem using Explorer or Chrome

I have all the defaults set correctly

I have run the Live Mail Repair fix

I  temporarily disabled my antivirus programme as I thought it may be blocking, but no luck.

I have experimented with changing some settings in Live Mail, but no luck so changed them back. 

I have read a lot of forums and haven't found anyone with this exact problem.

I'm not an expert, but am fairly good at finding answers - this is the first time I've had to actually ask for HELP!!!

So please help!

Thanks.