IIS Hangs after DSL Outage

We recently suffered through a day with four totally seperate locations all using Qwest DSL with Cisco 675 Routers when the DSL service kept dropping. All four of our web servers began to experience the exact same failures. After the DSL would come back up, IIS would run for a while then hang. IIS manager showed that the web site and SMT were running. If we stopped the Web Site it would display stopped but when you restarted it you would get an error message that it could not bind to the instance. If you started it a second time it would come back up. The SMTP service needed to be restarted in Control Panel Services. There are not events logged in event viewer. Has anyone run into this problem before and if so what can be done to stop it?