It’s very important in SharePoint 2007 to know how to reset a service account so that your websites don’t start getting the error “cannot connect to configuration database”. You have to change the service account password using the Central Administration webpage. In this guide I will walk you through the steps of changing your service account password using the SharePoint Central Admin webpage.
When you change your service account password in Active Directory you usually then have to change the password where ever it is used in Windows. This isn’t exactly how you update the password with SharePoint 2007. With SharePoint 2007 you have to update the password using SharePoint 2007. The reason you have to use the SharePoint Central Admin page to update the old password is because the old password is stored in the content database and SharePoint references it from within this Database. So even if you change the password say in IIS and for each service that is running SharePoint within Windows, the SharePoint password that is stored in the Database is going to be the one SharePoint recognizes (this will be your old password until you update it through the console).
So in order to properly change the password to your Service account you need to follow these steps:
Open Central Administration Webpage
Click the Operations Tab
Click Service Accounts Link (Security configuration section)
Click on Web Application Pool Radio Button
Click Web service drop down (choose Windows SharePoint Services Web Application)
Click Application Pool drop down (choose application pool you want to reset)
Type in new Password for Service account (you can also assign a new service account by entering the service account username in place of the existing user name)
Repeat above steps for all other service accounts
You should get a display page that tells you the service account password was reset successfully, if you get an error on the page you probably mis-typed the password or username, go back and try it again. Make sure you are typing in the right username and password. Once you have reset all of your service account passwords then make sure you test all of your sites and other SharePoint functionality to make sure that you aren’t getting any more errors or password failures (check security log files in Windows). If everything looks good then you are finished. Hope this guide helps you to reset your service account passwords in SharePoint 2007.