Trojans are malicious applications that pose themselves as legitimate software in order to trick users to install them. Once on the victim's machine, it may run any number of malicious process to steal vital information or inflict damage to other software.
From the Vendor: 'First of all, click on 'About' on the client for help. The ICQ notify will _NOT_ page you _unless_ you enter YOUR ICQ UIN in the icq notify box and click notify. Then it will start paging you. Every time the victim gets on. The screen capture is slooow! It should be fixed in next versions to come! So you will have to live with it. If you need help or have a bug to report, please visit the forum that is shown in the 'ABOUT' on the client. But it pretty much runs awesome.'