I just reinstalled Exchange 2007 on Windows 2008 in Hyper-V and I was coming across an error with the ISAPI Filters.
Event ID: 2268
Raw Event ID : 2268
Record Nr. : 3746
Type : Error
Machine : EX2007EDU
Could not load all ISAPI filters for site “Default Web Site”. Therefore startup aborted.
Basically, this happened where the site where OWA is installed is either a 32bit mode or ASP.NET 1.1. Since Exchange 2007 Outlook Web Access 2007 only runs on ASP.NET 2.0 in 64bit mode, you need to fix it back.
First, disable the 32bit mode for your web site. By default OWA goes into the Default Web Site context (0) so the following will take care of that:
cscript C:\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0
Second, register ASP.NET 2.0 as the default framework for that web site:
Start installing ASP.NET (2.0.50727).
Finished installing ASP.NET (2.0.50727)
Restart IIS and you should be all set.