Hi,
I'm a member of the Searchnu Support Team. I'm here to help
Excuse me, my French is not so good so I will write in English.
When the software was installed onto your pc it offered two basic installs, typical installation, which lists the add-on features such as searchnu default search, and Custom installation, which allows you to select the add-ons that you wish to install. There's no need to worry if you did the typical install - this isn't a virus,nor malware, and there's no need to Perform a virus scan against it.
If you wish to uninstall Searchnu please follow the instructions below:
Go to Control Panel > Add/Remove Programs > look for windows searchnu toolbar > Uninstall
Thanks in advance.
The Searchnu Support Team