Sounds that the JavaScript (do not confuse JavaScript and with the Java plugin) that is responsible for refreshing the mails isn't working.
I'm not using the Outlook.com website, so I don't know if there are issues with it in current Firefox releases.

You can try to create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

There have not been any updates to Win7, Firefox or new javascripts between when outlook.com was working 3 days ago and today so creating a new Firefox profile does not make a lot of sense.

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

Clear the cache and cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

I'll try the above in the morning and update. Thanks

I tested in Safe Mode and the behavior changed. The email from gmail was received in Outlook.com inbox immediately, new mail notification in the Firefox tab did not appear.

I exited Safe Mode and tested again. email was received in Outlook.com immediately but new mail notification still did not appear in Firefox tab.

I'll go through the troubleshooting extensions, etc next

The problem is not with extensions, themes or hardware acceleration.

I have no idea what fixed the receiving of new email in Outlook.com after testing in Safe Mode but after after exiting Safe Mode back to running Firefox as normal at least I am receiving new emails immediately.

I guess this will remain a mystery of the computer universe.

Thanks for your suggestions.

If you are talking about Outlook or Outlook Express from Microsoft, they are outdated programs. The current program is called Windows Live Mail.

Outlook.com the piece of garbage that Microsoft said was replacing Hotmail.

THIS PROBLEM FIRST OCCURRED AFTER I WAS UPDATED TO V29, IT DROVE ME A LITTLE CRAZY! THE TIME & DATE WERE VISIBLE, BUT, THE SUBJECT TEXT WAS MISSING.

I FIXED THE PROBLEM BY REINSTALLING AN OLDER VERSION (V23) OF FIREFOX - THE PROBLEM IS NOW GONE!

I'M SURE MOZILLA WILL GET THIS CORRECTED, HOWEVER, IN THE MEAN TIME, I WILL USE AN OLDER (WORKING) VERSION OF FIREFOX.