Constant Connection Drop

My Windows 2003 SBS Server keeps dropping its connection to XP Pro machines
every 10 minutes or so but doesnt disconnect vista machines, i also found
that after the most recent set of updates the servers logging to email
facility keeps saying "Host Name Invalid" and shows no details. Also when i
installed Sharepoint 3 along side version 2 on sbs as instructed how to do
so all my remote access sites have gone and i cannot even get the web site
up as it now says page not found.

Any ideas?


Thanks in advance Matt