I would check that the plugins installed are the correct, latest version. To do this, go to the [http://mozilla.com/plugincheck Mozilla Plugin Check site]. Once you're there, the site will check if all your plugins have the latest versions. If you see plugins in the list that have a yellow ''Update'' button or a red ''Update now'' button, please update these immediately. To do so, please click each red or yellow button. Then you should see a site that allows you to download the latest version. Double-click the downloaded file to start the installation and follow the steps mentioned in the installation procedure. Also, see if the [[Troubleshoot Firefox issues using Safe Mode| Safe Mode]] determine the cause of the problem..

You should also try Windows [http://windows.microsoft.com/en-US/windows-vista/start-your-computer-in-safe-mode safe mode] and see if its a driver problem.