Kick/ban the user from the channel and then /ignore them. Also enable flood protection in Alt+O -> IRC -> Flood and make sure to limit CTCP replies, whois requests, query windows, etc.
thanks for the help
some times i cant kick/ban the user because some times i entered the channel and leave the lap top
i did the protection now but i dont understand these "
and make sure to limit CTCP replies, whois requests, query windows, etc. " can you explain it in Pics if you can