It may be that you have a lot of add-ons and plugins,and some interfere with Firefox or each other, especially if they are not all up-to date, but first of all maybe I should ask some obvious questions:

• are they enabled ?
  (Check using the menu from the Orange Firefox Button)
• is AdBlock or any other software set to block sites or features that may produce these symptoms
• What is SaveSesion ?
  (Is that the Firefox feature that offers to restore your session, or restart)
• The More system details ... aside only lists your plug-ins but not your add-ons and extensions,
  so what add-ons are you using, or trying to use ?

I have many add-ons which are working correct until yesterday and all are up-to-date.

• yes they are enabled
• no software blocks sites, only AdBlock blocks some ads,images,videos,frames.
• Save Session is another add-on : saves session and exits and restores when started
• About 20 add-ons are installed, I added them to a collection

My add-ons

I don't know what happened, but all of them started working now..!!

I have another problem, sometimes. When I start browser sometimes the sync says account and password are not matched.When I type and click on Update password it says incorrect details and when i click it again it says password updated and shows my sync account.

Which security software (firewall, anti-virus) do you have?

Some security software has virtualization features that can cause problems by protecting and restoring files in the Firefox profile folder.

I use Microsoft Security Essentials, Panda AntiVirus and Comodo FireWall