I have occurences on two seperate Vista Business laptops where the network just fails.This appears as Outlook 2007 asking for the user name and password - where the machine can not find Exchange. I am running under a Windows 2003 domain.I cannot then restart the machine as it hangs "Logging off". After the forced restart everything is ok until it happens again - usually every day. XP machines never to this.This has happened on two machines now - a HP 6400 and now a Lenovo T61.I am a bit fed up now..

Same issue with Vista ultimate computer work station. No Problem logging on to Win 2003 enterprise server. Usually after idle time the connection is dropped and thedatabase application that was idle searches with the blue rotating circle in vain.You cannot end this endless loop even using taskmanager or ending the process. When you try and shut down or restart you just see the logging off screen which remains until you hard power down. upon reboot everything works fine. I have updated to the lastest ethernet driver, disabled the IPV6 tcip, turned off power saving features. I connect to the server through a linksys router were both the server and workstaion are hard wired to the router. Would love to have some other options to try, Thanks

I raised a case with Microsoft. They advised the following from a command prompt under Run As Administrator:- Netsh interface tcp set global autotuninglevel=disabled I think this has helped but I still get the occassional lock up still. Regards