NIS2009 install over older version.

I have what, I hope, is a simple question.

 

I have NIS 2009 Premium Edition, three user [UK] that I have successfully installed in a new PC. Now I want to install in it an older back-up PC.

 

That PC has an ISP supplied version of an earlier NAV (SKU: 1051584-IN) which I believe may be the 2005 version, [provided by BT Yahoo]. The free Norton Av is due to be discontinued and, to get their latest offering, I would have to change my contract conditions, something I do not wish to do.

 

Windows>Control Panel>Add/Remove programs does not show Norton as an installed program and, therefore, there is no way to remove it.

 

Should I just go ahead and install NIS 2009 and hope that it removes all traces of the earlier version or should I first run the Norton Removal Tool, which I have downloaded, before installing the new version?

 

Kind regards,

 

John