Google is bringing up nothing on this subject for me.
We had an administrator accidentally delete the "Default Web Site" rather than the virtual directories following these instructions http://support.microsoft.com/kb/883380. Now everything in ESM is grayed out when you right click the virtual server:
I recreated the "Default Web Site" and then tried the KB article method 1 again, but it didn't recreate the virtual directories in ISS and the virtual server is still grayed out. I've tried rebooting, I even tried reinstalling service pack 2 with no success. Why will Exchange not recreate the virtual directories? I assume it had some linking (maybe a registry setting) to the old "Default Web Site"?
Edit: I just tried method 3 in that KB article and no success either. Still just an empty "Default Web Site":
Edit 2: Solved (see comments).
Best Answer
I'm betting the issue was that "Default Web Site" was not using the identifier of 1. Even when you manually create a site and name it "Default Web Site" you'll notice in your Web Sites list that the identifier is random and Exchange is only looking for 1. Here's an example of a process (I've not tested but have used something similar in years past) that "gets you back to 1" on the default site... which your IIS restore did for you.
http://www.dotnetscraps.com/dotnetscraps/post/Did-you-know-How-to-recreate-e2809cDefault-Web-Sitee2809d-in-IIS-7-75.aspx
We all learn after making this mistake once, that the Default Web Site is special and unique and can't easily be recreated, so we leave it be :). Now your Administrator is one of us.