Change the Default Language
https://support.mozilla.org/en-US/kb/change-default-language?cache=no
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Adblock Plus için Element Hiding helper <--remove this
BetterPrivacy <--remove this
Flash Block (Plus) <--remove this
You can simply disable Flash in the addons manager, and my thoughts are AdBlock for Firefox blocks FlashPlayer.
Ramblock <-- not finding any good information related to this plugin
Restart <--should be able to manually restart Firefox on command
Time Restart <--I personally think this is unnecessary, should be able to restart when needed and not setup to a time you think it's needed.
Microsoft.Net Framework Asistant(disabled)<--leave alone
it's also possible that Mozilla is blocking the .NET plugin due to pretty serious security exploits out there.
Firefox troubleshooting link
https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram?cache=no
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Adblock Plus for Opera
https://addons.opera.com/en/extensions/details/opera-adblock/?display=el
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sounds more like the message is telling you that the browser and website can't arrive at a mutually agreeable https protocol.
Type "http://" in the beginning of the url.
Have you tried to disable any antivirus/firewall temporarily
What happens if you try a different browser?
Opera 36 is the latest Opera version that supports XP
Opera help forum
http://forums.opera.com/discussion/1883427/this-site-cant-provide-a-secure-connection/p1
