antivirus for MS exchange 2003

hi greetings all

my company just want me to upgrade for MS exchange for their new proj.
and i m working at my lab environment.i face following problems

(1) is there any antivirus specific for exchange server. is nod32 feasible for it?or any other will do better?

(2)im running my exchange 2003 on windows server 2003 (without service pack),after installing exchange my pc taking ages to shutdown ,if i swithed it off directly exchange crashes down

is there any way to prevent crashes and improve shutdown speed? is there servicepack available? please let me know.

im running exchange on cel 2.53ghz,40gb,256mb RAM,intel chipset board

please help me

any assistace woud be grately appreciated


thank you!