How are you.
If you are using Netscape 7.2, the full suite, you need to go not to Netscape 9, which is right now a browser only; but to SeaMonkey 1.1.4, which is a full suite with browser, composer, and email. Netscape 9 will eventually have an email utility, but there are no plans for a suite like Netscape 7.2.
If you are not a suite user, just using the browser then by all means Netscape 9 is good.
Also, you can use Netscape 9 with Thunderbird.
The very worst thing you can do is stay with Netscape 7.2. First, it is not really Netscape. It is really re-packaged Mozilla Suite from the Mozilla Foundation, which now produces Firefox and houses SeaMonkey and Thunderbird. It has not been updated, even for security for a long time.
If you switch to SeaMonkey, your profile and everything else should translate over invisibly and seamlessly with no hitches.
Any problems and questions can be handled by the very able folks in this forum.
Best of luck, welcome to the club.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:18.104.22.168) Gecko/20070914 Firefox/22.214.171.124