This is a serious matter, I am asking for assistance.

1. A 'user' loads MSN Messenger and sends confidential company information to
to a 'friend'.

2. Have tried blocking MSN's port 1863, but it then uses HTTP proxy port
(thanks MS !!) Then tried blocking all the MSN IPs, but it still goes through.

3. Tried 5 different keyloggers, but A/V keeps picking them up.

4. Have put a sniffer on the users IP, but the buffer fills up. And not knowing
what day the messages will be sent.......

5. Blocked the IP address at the router, but the user goes to another computer.

6. Installed MS 2000 Professional on sensitive computers.

All systems are Windows based (and I'm not strong in Linux)