This issue relates to either cookie storage is corrupt or the browser itself.
Well, I did a quick research and found out some things that may help you.
1. Got to Start>>Run
2. Type in %appdata% and hit OK.
4. Find Mozilla >> Firefox >> *xxProfile*
5. You will see the cookies.txt (if it exists) and cookies.sqllite files
6. Delete both of those files and reboot.
See if it works.
Here's a few more options:
Go to Tools -> Options -> Privacy and make sure that you uncheck "Always clear my private data when I close Firefox".
Go to Tools -> Options -> Privacy. Make sure that the following settings are true
- "Accept Third Party Cookies" and "Keep until they expire".
Restart FF and reboot see if it works.
Regarding Reinstalling FF.
Reinstalling FF is simple and you will keep all of your settings and I think even your add-ons. It takes just a few minutes. I would recommend doing that.
Reinstalling Firefox will remove all passwords and bookmarks. Don't know if that changed though but for the earlier version.Export bookmarks in Firefox
In Firefox, click on Bookmarks>>Organize Bookmarks>>Import and Backup>>Export as HTML
Save it to your desktopExport Remembered Passwords
In Firefox, click on Tools>>Options>>Security>>Saved password>>show passwords
Take a screenshot of the screen
Alt+Prnt Scrn buttons
Woops, forgot to mention, open MSPaint from Start>>All Programs>>Accesories>>Paint
Click on EDIT>>PASTE
Save it to your desktop.
Also, I suggest you remove the following two folders after uninstalling FF and before reinstalling FF.
C:\Documents and Settings\HP_Administrator\Application Data\Mozilla\Firefox
C:\Program Files\Mozilla Firefox