After running the Sharepoint products and technologies configuration wizard successfully, the central administration site page opens up.
( We were installing MOSS 2007 on 64 bit machine)
But in my case it was giving the following error
Checking into event log gave the following information
Could not load all ISAPI filters for site/service. Therefore startup aborted.
ISAPI Filter ‘C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_filter.dll’ could not be loaded due to a configuration problem. The current configuration only supports loading images built for a AMD64 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.
Searching for it the solution that I found was the following
// Disabling the 32bit mode for your web site.
cscript C:\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0
and then the following
// Registering ASP.NET 2.0 as the default framework for that web site
This resolved the issue for us!!