Services stopped

Hi
We have two two sites. Each one with a win2000 server.
The sites are connected via VPN and are running Exchange 2000

In both sites we have the problem that, when we start the www publishing service, the following services are terminated unexpectedly after a few minutes (or sometimes after a few hours)
– IIS ADmin
– IMAP4
– FTP
– NNTP
– POP3
– Exchange Routing Engine
– SMTP
– WWW publishing

The event log only tells me that the services were terminated unexpectedly with eventid 7031(no information on the data field)

Note:
If I keep the www service down, all the services work without a problem.