There may be a corrupt file preventing the add-on from working. Follow the procedure for corrupt extension files in the unable to install add-ons article to see if that fixes your problems.

You can also check to see if the WOT icon is shown in the customize toolbar dialog, if it is try adding it to the toolbar. For details on how to do this see how to customize the toolbar.

Another possibility is the file that stores toolbar customizations is corrupt. To test this can you add other icons to the toolbar and do they remain when you restart Firefox? If they do not see toolbar keeps resetting.

I tried everything you said. But it's still the same! What will I do? Let me reinstall firefox and see whether it will work. I will post after that.

Try to reset the network.http prefs on the about:config page that are bold (user set).
Not all website may work with http pipelining enabled or with increased max connections.

network.http.max-connections 48
network.http.max-connections-per-server 16
network.http.max-persistent-connections-per-proxy 16
network.http.max-persistent-connections-per-server 8
network.http.pipelining true
network.http.pipelining.firstrequest true
network.http.pipelining.maxrequests 8
network.http.proxy.pipelining true
network.http.request.max-start-delay 0

See http://kb.mozillazine.org/about%3Aconfig

See also http://kb.mozillazine.org/Resetting_preferences

Thanks friends for your help.....but it is still the same...! And @ cor-el : What you said me to change was already in default(same).....so I didn't change anything. That program works on Google Chrome and Internet Explorer but not on Firefox. I only like Firefox because it is the BEST but now....! :-(

Is your Persona hiding the button? Try changing to the Default theme to see if you can see your WOT button. See: https://support.mozilla.com/en-US/kb/Using+themes+with+Firefox

Have you visited the WOT site?

• Main page: http://www.mywot.com/
• Main Support page: http://www.mywot.com/en/support
• Info about missing toolbar button: http://www.mywot.com/en/download/faq#ff-toolbar-missing
• FAQs: http://www.mywot.com/en/download/faq
• Tutorial: http://www.mywot.com/en/support/tutorials
• Forum: http://www.mywot.com/en/forum

Update Shockwave Flash (Adobe Flash). A new version was released last week.

1. You can check your version: http://www.mozilla.com/en-US/plugincheck/
   • Note: plugin check page does not have information on all plugin versions
2. Use Firefox to Download and SAVE to your hard drive (link in article below)
3. After download completes, close Firefox
4. Click on the file you just downloaded and install
   • Note: Vista and Win7 users may need to right-click the installer downloaded and choose "Run as Administrator"
   • Note: Most browsers other than IE will also get updated with this one download
   • Note: To update IE, same procedure but use IE to go: http://fpdownload.macromedia.com/get/flashplayer/current/install_flash_player_ax.exe
5. After installation, restart Firefox and check your version again.

Download link and other information: https://support.mozilla.com/en-US/kb/Managing+the+Flash+plugin#Updating_Flash

Update Java

1. You can check your version: http://www.mozilla.com/en-US/plugincheck/
   • Note: plugin check page does not have information on all plugin versions

See: https://support.mozilla.com/en-US/kb/Using+the+Java+plugin+with+Firefox#Installing_or_updating_Java

I have personas and put default theme, still I'm facing that problem! I put the question in the WOT support forum, many people are replying but still it is not solved. Do you need any Screenshots? If so, please reply...I'm glad to provide you information because I need to solve the problem so that I can browse securely  :-)