Mohan,
- Go to somebody else computer, log into Windchill and check if the home page comes up without issues. Does it come up?
- If 1 above is true, can you duplicate the issue on your PC using multiple browsers (ie, Chrome, Firefox)?
- If 1 above is true, did you delete all cache from your browser then restarted your PC and tried again to access the home page?
- If 1 above is true, ask somebody to log onto your PC and access his home page. Does it work?
You may also experience stickiness 
on your user ID for some reasons ... access the URL below (replace with your server name) and click on Reset Server Stickiness.
- http://<Server_Address>/Windchill/app/netmarkets/jsp/user/utilitiesList.jsp
Regards,
Terry