but the last thing I would (almost) ever want to do is to call these people up personally.

Most of these nowadays are thugs and organised criminal orgainisations and not your old fashioned 'script kiddies' who were distributing malware just for the kicks.

Think Russian Mafia, Nigerian Government sponsored scams, Far Eastern Government DDOS and other malware attacks, etc, and you might get the idea.

Of course if you were interested in the business yourself they might be kinder to you, but they might just as easily roll you over, kick you in the teeth, steal all your personal information anyway, then offer you a job so you can 'pay off your debt' to them. The interest rate would be substantial though.

But for us normal innocent folk, best let the authorities handle it. They've been trying for years, but cross-border cooperation is sorely lacking at present.

There may be clues in the XP Antivirus 2012, (and so many similar), windows themselves. Think - "Contact Us". But personally I wouldn't touch that with a barge pole.

Good luck.