Open menu "Tools" in the top bar window of the Opera browser and go to "Advanced" to specify the installed plugins.
Select "Plugins" and read the list.
Return to menu "tools" and select "Quick preferences" to enable/disable installed extensions.
Click "Enable plugins" and perform the required operations. The General principle of installation of the extensions you need is to move the file NSAPI4 having the form imaplogin.plugin, into the directory /Library/Internet Plug-ins/ and restart Firefox. The desired extension is displayed in "Tools" -> "Advanced" -> "Plugins".
Download extension Adobe Reader from the official site http://get.adobe.com/reader/ and restart the Opera browser to install this plugin manually.
Download Adobe Shockwave Player from the official Adobe website and close Opera before installing.
Run the extension installer and make sure that the list of selected browsers Opera. Otherwise, click "Browse" and specify the path C:Program FilesOperaProgramPlugins.
Download the extension Adobe Flash Player from the official Adobe website and open the disk image.
Double-click on icon Install Adobe Flash Player.
Wait for the installer warning of the need to complete the work , close the browser and Opera.
Download the extension Perian from the official website and open the disk image.
Double-click on the shortcut Perian.the prefPane to start the installation of the plugin.
Restart the settings panel for the start of the expansion.
Download the extension Silverlight from the official website and open the disk image.
Double-click on the installer icon and follow the prompts of the installation wizard plug-in.
Restart Opera for applying the selected changes.