Problem :
Firefox will not start and no error message is shown
Solution :
1. Right-click on an empty spot in the Windows task bar and select Task Manager (or press Ctrl+Shift+Esc).
Note: On newer versions of Windows (XP, Vista, 7) the combination Ctrl+Alt+Del opens Task Manager as well.
2. When the Windows Task Manager opens, select the Processes tab.
3. Select the entry for firefox.exe (press F on the keyboard to find it) and click End Process.
4. Click Yes in the "Task Manager Warning" dialog that appears.
5. Repeat the above steps to end any additional firefox.exe processes, if more than one entry is found, then exit the Windows Task Manager.
6. Start Firefox normally.
7. At the top of the Firefox window, click on the Tools menu, and select Add-ons.
8. Select the Extensions panel.
9. (If it is listed) Select Norton IPS and click Disable.
10. (If it is listed) Select Norton Toolbar and click Disable.
11. (If it is listed) Select Skype 4.0 and click Disable.
12. Click on Restart Firefox.