Odd one here. I tried to run Trend Micro Housecall (I've done so before but not for a couple of years). It wanted to download and install a plugin for Netscape.
But I don't use Netscape. I use Mozilla (v 1.7RC1 at the moment), and it couldn't find the Netscape Plugins folder so refused to go any further. I showed it the Mozilla one, but that didn't satisfy it.
Sounds like Mozilla is even more secure than I thought!