Exchange 2K Virtual Server Crashes

I am somewhat new to the Exchange realm, causing me to have a relatively basic question. Our SMTP virtual server seems to crash on a regular basis (about every other day). This seems absurdly often, even for a Microsoft product. My problem is: I don't know where to start troubleshooting. I'd hate to call Microsoft and find out it's a very basic switch somewhere and if I had any experience whatsoever it would have been exactly where I would have started. Can anybody start me off?