Try exiting Firefox, then removing the pluginreg.dat file from the profile.

Are you deleting cookies when you exit Firefox? Check Options > Privacy > Settings (next to "Clear history when Firefox closes") and ensure that Cookies is not checked.

This can be caused by corrupted cookies.

• https://support.mozilla.org/kb/fix-login-issues-on-websites-requrie-passwords

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

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

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

If clearing cookies doesn't work then it is possible that the file cookies.sqlite that stores the cookies is corrupted.
Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted.

• http://kb.mozillazine.org/Cookies

Your above posted system details show outdated plugin(s) with known security and stability risks that you should update.

• Shockwave Flash 10.0 r42

You can set the plugin.expose_full_path pref to true on the about:config page to see the full path of plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins
• http://kb.mozillazine.org/about:plugins
• http://kb.mozillazine.org/about:config

It is best not to leave that pref set to true as it exposes that full path to web servers via the navigator.plugins object, so reset that pref to false after you are done with the about:plugins page.

See "Manually uninstalling a plugin":

• https://support.mozilla.org/kb/Troubleshooting+plugins

• http://www.adobe.com/software/flash/about/
• http://helpx.adobe.com/flash-player.html

"Try exiting Firefox, then removing the pluginreg.dat file from the profile."

Wish I knew how to do that!

"Are you deleting cookies when you exit Firefox? Check Options > Privacy > Settings (next to "Clear history when Firefox closes") and ensure that Cookies is not checked."

No 'settings' next to "Clear history when Firefox closes" in my Options > Privacy . I have downloaded the latest version of Firefox btw.

Sorry to say I've almost no idea what most of the second reply means.......and I'm no newbie to all this ;-)

eg......You can set the plugin.expose_full_path pref to true on the about:config page to see the full path of plugins on the about:plugins page.

Hmmmm. Where does one start with that??!!

Oh, and by the way. "Remove Cookies" from sites causing problems: Tools > Options > Privacy > Cookies: "Show Cookies"

No 'show cookies' option that I can see, and I have looked hard!

To see all the history and cookie setting, select:

• Tools > Options > Privacy > History: Firefox will: "Use custom settings for history"

• https://support.mozilla.org/kb/Options+window+-+Privacy+panel

Thanks for that. Have found and deleted cookies.

Part of the problem was with a BT/McAfee product called net Protect Plus which I've taken off and then re-installed.

Still getting 'some plugins used by this page are out of date'.

'Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted' Where/how???

Thanks again.

Martin