IIS crashing – when the IIS process restarts without any explanations. The threads running web requests are protected from exceptions by catching the exceptions and deliver a error page (the nice gray and yellow page) otherwise the application should terminate. There are several exceptions that seem to be unrecoverable such as OutOfMemoryExceptions, StackOverflowException and some more.
The normal way of trouble shoot this kind of crashes are by first examine the event log to see what causes the exception and maybe take a memory dumps when the process crash with adplus –crash argument.
Example
adplus -pn w3wp.exe -crash
Troubleshoot a StackOverflowException - the event log reports error code 0xE053534F