whats the bookmark info? If you go to gmail.com manually does it work? or you mean the gmail icon on google apps?

I don't use a bookmark. I type gmail.com in the url space manually. I have tried gmail icon in Google and it does not work either.

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You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.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 remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" for websites that cause problems:

• Options/Preferences -> Privacy & Security
  Cookies and Site Data: "Manage Data"

"Clear the Cache":

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Clear Data -> Cached Web Content: Clear

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can remove all data stored in Firefox for a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox for this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data for that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data for that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

Thank you for prompt reply and your ideas about now to solve this problem. Unfortunately I am not a techie and I cannot follow your instructions. First of all, what page am I supposed to be on when I start? The main menu when I open Firefox or the one blank page I get when I try to open gmail? I do not know what a reload button is, and anyway you can only left-click on a mouse, not a button. When I open gmail in Firefox a largely blank page appears with https://mail.google.com/mail/u/0/ in the url space at the top and that is as far as it gets. When I open it in Chrome, the same blank page comes on, but then the red envelope appears and a new page comes on with my Inbox or wherever I left off the last time I was logged on. The red envelope and new page are not appearing on Firefox. I have tried to find my Gmail several ways on Firefox; for example, adding #inbox to the url, but nothing further happens. All other sites in Firefox are working properly. I am not sure what you mean by "websites that cause problems". Do you mean the gmail site itself, or other websites that may be preventing me from getting onto my gmail? Hopefully my explanation of what precisely happens will give you other ideas on how this matter could be addressed. When you reply it is best to assume that I am pretty lousy at figuring out these technical matters and will need very precise instructions.

The first thing you can try is try loading gmail and then press control key + f5 at the same time to bypass the cache and reload the page properly.

If that doesn't work, go to your options menu (the three bar menu icon on the top right) and click options -> Privacy & Security Cookies and Site Data: "Manage Data" and delete the cookies

and also try Clearing your Cache":

   Options/Preferences -> Privacy & Security
   Cookies and Site Data -> Clear Data -> Cached Web Content: Clear