Installed: SharePoint Server 2010 for Internet Enterprise Beta (x64) On: Windows Server 2008 Standard (x64) on 64 bit hardware
Attempts to access the Central Administration console led to IIS returning 503. The service is unavailable
And this error was found in the Application log
The Module DLL ‘C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\isapi\owssvr.dll‘ could not be loaded due to a configuration problem. The current configuration only supports loading images built for a x86 processor architecture.
After much ado, the solution turned out to be:
1) Ensure that the enable32BitAppOnWin64 seeting for the "SharePoint Central Administration" app pool is set to False, and the same for the "SharePoint Web Services Root" app pool
2) Edit applicationHost.config:
Change:
<globalModules>
...
...
<add name="SharePoint14Module" image="C:\Program Files\Common
Files\Microsoft Shared\Web Server
Extensions\14\isapi\owssvr.dll"
preCondition="appPoolName=SharePoint
Central Administration v4" />
</globalModules>
To:
<add name="SharePoint14Module" image="C:\Program Files\Common Files\Microsoft
Shared\Web Server Extensions\14\isapi\owssvr.dll" preCondition=
"appPoolName=SharePoint Central Administration v4,bitness64" />
I hope this helps somebody :-)
bitness64 being the magic word here
Solving SharePoint Server 2010 - 503. The service is unavailable, After installation
原文：http://www.cnblogs.com/huaan011/p/4058155.html