My Exchange 2007 server suddenly stopped delivering all mail. The problem is I can't diagnose anything because when I try any of the tools they don't work: queue viewer fails after about 3 minutes with "the remote procedure call was cancelled". Routing log viewer hangs and never does anything. Message tracking found exactly one message of status RECEIVE and absolutely nothing else, yet messages are being delivered to the server via SMTP.
I can't think where to look and am at the end of my wits here!!! Any help gratefully received.