How I can use Yahoo / MSN Messenger, as I'm sitting behind a corporate firewall, I have dial-up connection via RAS?

I am using this connection through a RAS, with 33.6 kbps modem connection, certain files to chat, they are blocked by the administrator of my network, I have also enabled through HTTP Proxy connections but this does not help, I am actually using a proxy address, where my account is authenticated by a username and password, then I'm connected to a remote computer, I am not enrolled in a corporate network, but this team will not let me use MSN / Yahoo Messenger, all records are created in this remote computer, do not have sufficient privileges to change the settings from this machine, but even meebo.com chat html could not help me.I can not approach my network administrator, please help, is there a cost-free software in the network to download, which will overlook this and solve my problem.Even of Google's gmail chat is disabled, please tell me how do I use I am using Win XP, 256 MB DDR SDRAM 400 MHz for a solution that does not bother my desk Security?

Trillian of Curel Stuidos

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