SharePoint Site Error 503

SharePoint Site Error: Service Unavailable HTTP Error 503. The service is unavailable

** when we traced back the recent changes we could identify that from the CA Search Administration 'reset all crawled content' option was recently triggered which ended up with SSP page error 'Service Unavailable HTTP Error 503. The service is unavailable'. 

** other possible reason could be if you change the identity or account password either directly from IIS settings or if at all from web config file.

** another reason could be if you install another web based program or add feature.. unexpectedly causing IIS to stop the SharePoint services. for. eg: if you install AD on the same machine, OR added a new web site with a duplicate port.

make sure  that Web site protocols starts properly and the user account used to start Applicaion pool is correct and starts as well.

steps:

i.  Open up IIS Manager and click on Application Pools.

ii.  Locate your App Pool account and right-click on it and select 'Advanced Settings'.

iii. Click on the right of the Identity box to change it (A window will pop up).

iv. Click on Set and simply retype your App Pool Identity in there with the new password.

List stored user names and passwords

Start > Run > type "rundll32.exe keymgr.dll, KRShowKeyMgr"

Windows 7 Domain Account Lock Out issue

Clear cached credentials from Windows Profile:

1) remove passwords by clicking on Start > Run > type "rundll32.exe keymgr.dll, KRShowKeyMgr" and then delete the Domain-related and if required other stored passwords.
2) remove passwords and Cookie information from Internet Explorer > Tools > Internet Options > General > Delete Browsing History > Delete > check Passwords checkbox and Cookies check box and Delete.
3) Disconnect all networks drives (pls make a note of the mappings), reboot, then map them again

also try these steps: Click Start, click Run, type Control Userpasswords2
select advanced and click manage passwords. Remove all stored passwords from both web credentials and windows credentials.

a helpful article form microsoft where you can download the account lockout status tool and troubleshoot accordingly http://social.technet.microsoft.com/Forums/en-US/w7itprosecurity/thread/0f88e0b6-7aa0-4917-bd06-68f77f14493e/