Systems Administrator

i have a windows 2003 server domain and my problem is that client machines running windows XP take more 10 minutes to logon somtimes. what could be the problem?

secondly my outlook 2003 takes too long to send mail and sometimes fails. but when i ping the Exch server 2003 i get a normal reply. Any quick solutions to my problems.

kmatabula@finca.co.zm
kmatabula@yahoo.com