You will need
  • program ICQ/QIP
Install QIP and run it under his ICQ number and the correct password.

Click the icon with the magnifying glass — the window opens search for people, was the messenger.
If you already know the number of the person you want to chat — just type in the box "Search ICQ #" to the desired number and click "Search". Also here you can get name, surname, patronymic and nickname of the person you need if you don't know his number.
If you want to specify more search parameters click "Advanced search" or "Global directory".
Here you have a lot of prospects in search of interesting people — you can indicate the gender of the desired person, his age range, city of residence, keywords, interests, occupation, and even marital status. Click search with the installed tick "online Only" if you need people online, or regular search, if you want broader results. Below appears the list of users that fit your parameters. The search won't take more than a few seconds.
You can consider the User Info of each one (user data) and to select the most appropriate interlocutor, and then double-click on the user and send him a message. You can also add a user to the contacts list from the search window, to request authorization and to allow the addition to your list, if you do require authorization.