Many problems with plugins can be solved by updating to the latest version of the plugin. You may need to uninstall and then reinstall the new version of the plugin that causes problems. See the Popular plugins article for information about reinstalling various plugins, and for troubleshooting steps for specific plugin problems.

If updating to the newest version of the plugin or reinstalling it does not fix the problem, you can leave it disabled.

Manually uninstalling a plugin
If you can't use an uninstaller program to remove a plugin, you can remove it manually:

In the Location bar, type about:config and press EnterReturn.
The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!, to continue to the about:config page.
Search for the preference: plugin.expose_full_path.
Double-click on the plugin.expose_full_path preference in the list to change the value to true.
Enter about:plugins into the Location bar to display the About Plugins page.
Each entry in the About Plugins page will have "File name:" followed by a path. Use Windows Explorer to navigateNavigate to the folder shown for the plugin you want to remove.
Rename the file to something other than its normal name - e.g. npswf32 becomes Xnpswf32
The plugin will be removed.

Re-initializing the plugins database
In some cases, you may not be able to install or re-install a plugin. Re-initializing the plugins database may fix this problem.

From the menu at the top of the Firefox windowbar, select FileFirefox and then select the ExitQuit FirefoxQuit menu item.
Open your Firefox profile folder.
Delete the pluginreg.dat file.
Open Firefox
In the Location bar type about:plugins and press EnterReturn, to bring up the Firefox plugins list.