Eu acho que você precisa tentar removê-lo completo do seu sistema, parece que está fazendo referência à versão errada (ou que não é realista, tudo foi removido.
Before you proceed with removing Opera, it is important that you know where Opera stores its settings. In Opera, go to Help > About Opera. Under "Paths" in the About Opera page, look for the path to your preferences - the Opera6.ini file. Take note of this path, as it will be needed to completely remove Opera from your system.
- Uninstalling Opera
To uninstall Opera, open the Control Panel from the Start menu in Windows. In the Control Panel, open "Add or Remove Programs", and locate Opera in the list of installed programs. Click "Remove" to uninstall Opera.
Please note that this will not remove user created files and settings.
- Removing user created files
In order to completely remove an Opera installation, the following directories must be removed after performing a normal uninstall:
The folder you installed Opera to. The Opera settings folder.
If you chose not to use separate settings for each user when installing Opera, you will only have to remove your Opera installation folder. To find out if this is the case, look at the location of the file Opera6.ini, which you found earlier, and compare it to the path to your main Opera installation folder.
If the location of the Opera6.ini file is different from the location of opera.exe, you are using separate settings for each user, and will have to delete two folders manually.
Before proceeding, you may wish to take a backup of your files in case you wish to install Opera again:
http://www.opera.com/support/search/view/313/
To remove the remaining files on your system, simply delete the Opera installation folder. If the Opera6.ini is separate for each user (in a different location than opera.exe, make sure you delete the folder where this file can be found as well.
Eu também vi pessoas recomendarem esta ferramenta chamada Revo .