You'll need to log in to your account each time you connect to ICQ-Chat.
If you're using the Webchat you may just select “I have a password” and you will see a field to enter your password, you can then ignore the following steps.
The following steps are for IRC Clients, not the Webchat.
The simplest, and most robust, way to do this is to configure SASL, if your client supports it. If not, you can supply your login details, in the form <account>:<password>, as a server password and they will be forwarded to NickServ when you finish connecting. For example:
/connect irc.icq-chat.com.net 6667 YourNick:YourPasswordAnother way of logging in into your Account is using NickServ:
/ns identify YourAccount YourPassword