There are two possible scenarios. The first is to delete or rename the file activation.dll found in:

(NS6) C:Program Files\Netscape\Netscape 6\components

OR

(NS7) C:Program Files\Netscape\Netscape\components.

You can alternately use the Search function to look for activation.dll and delete it from the list once it is located.

The second solution (for Netscape 6) is to use your Windows Explorer or Search command to locate the file all-ns.js which is typically found under the C:Program Files\Netscape\Netscape 6\defaults\pref folder. You can open the all-ns.js file with Notepad and change the following entry:

pref("browser.registration.enable", true);

to look like this:

pref("browser.registration.enable", false);