>A regular IISReset /Restart turned into forcing a reboot. The stop worked but the start was unable to succeed.
>
>The message was:
>
>"Cannot start a new login session with an id that is already in use"
>
>IISReset /Start reported the same problem.
>
>NET STOP W3SVC reported the same problem.
>
>In hope of finding the proper svchost.exe to terminate, I ran "tasklist /svc" but was unablet to see W3SVC among the tasks handled by one of the svchost.exe instance.
>
>So, the last resort was to force a reboot.
>
>Anyone has seen that one before or would know how we could have resolved that in a smooth way?

I think inetinfo.exe is the task you wanted. Maybe w3wp.exe as well.

In Computer Management...Services, for each service you can see its properties, including the executable that gets run. The ProcessExplorer download can also show better information on running processes and what they represent.

If you get strange errors, you can check your various event logs for errors or warnings. Most useful are usually the System and Application event logs.