First off, no trojan can insert itself into your system by you simply opening a zip file. You have to execute the contents of that zip file (this means you have to run an .exe file, a .com file or a .bat file).

The porndial trojan is very easy to pick up, a number of warez sites have it set to auto-download on your system. It's annoying more than harmful, but it's ridiculously easy to get rid of - usually it just puts itself on your desktop or somewhere easy to find on your hard drive.

Also, trojans aren't just 'back door access' programs like netbus - a trojan is, by definition, a program that stays hidden. Beyond that, a trojan can have just about any purpose (usually malign) whatsoever.

If you DO have a trojan backdoor on your computer, don't panic. It doesn't do anything bad by itself, so there's a big possibility that your system is ok. All it does is leave your computer's ports open for scanning and access by people who have the correct client program. All I can say is GET YOURSELF A GOOD FIREWALL. I have no experience with ConSeal so can't say anything for or against it, but ZoneAlarm is good in that it allows YOU to control what programs can and can't access the internet from your computer. THIS IS A GOOD THING. Especially where backdoor access programs are concerned - if they can't get at your tcp/ip ports, then the threat they pose is nullified. You still need to get rid of them, tho (obviously :-) )

If you're comfortable with netbus et al and have a use for them e.g. remote access to your home system from work, good for you. Just make sure that you're the ONLY person who can log in that way!

As far as getting these files through gnutella goes, if all you do is use gnutella as a 'napster-a-like' system i.e. to search purely for .mp3 files, then you're safe. An mp3 file is basically a highly compressed .wav file - it's purely audio/video data, there are no executable components to it. It is NOT simply another kind of .zip file, the only thing you can put into .mp3s are audio and video.

So, in summary -

1. if you have a trojan, it's nothing to start getting all paranoid about. There's so many computers out there the chances are minimal that you'll be hit....

2. GET A GOOD FIREWALL!!! www.zonealarm.com (it's free...if you want to pay some cash, try that ConSeal program).

3. Just because you use Gnutella, it doesn't mean that yoou're automatically going to be getting trojans. Nevertheless, be careful.

4. Above all, USE YOUR NOGGIN (aka head). Don't do stupid things like downloading random programs without virus protection.

5. All of the above, reiterated twice for effect, impact and retention on your part.