Exchange server unavailable

[Greg]

This may be coincicdence but since my antivirus software
detected and quarantined the blaster worm I have problems
accessing my exchange mailbox via Outlook depending on
which LAN I am atached to. At my school we have a
cuuriculum and an admin LAN. If I plug my notebook into a
port on the curric LAN (where exchange server lives) I
have no problems. If I plug into a port on the admin LAN
I get the exchange server unavailable message. I can ping
the sever from the Admin LAN and Web outlook works. If I
use another workstation on the admin LAN I can open my
exchange mailbox via outlook.
My notebook is running XP pro and Outlook XP.
Obviously the problem is on my notebook.
Any assistance would be greatly appreciated. This is
driving me nuts.