App-pool problems, updating credentials in stsadm

I opened Sharepoint 2010 Central Admin and as per normal, was prompted for my login details. As I did not know the details, I closed after a few guesses/changing the default account.

A few hours later, remembering the password, I try again but get a 503 Service Unavailable.

I check the app pools in IIS7 and see that the SharePoint Central Administration v4 app pool is off. I turn it on, close IIS7, but it turns off again. Its settings look good to me:

Enable 32-bit applications Off Start Automatically True Enabled True

However, the application event log tells me that the account I was using to access Central Admin, and used by this app pool, has now expired (it's a local account so I did not know this will happen). This also impacts all other services such as SQL Server etc. How can I change the account of the app poo开发者_开发问答l, but also change all of the other service accounts?

The credentials used for the account [name] expired on 1/9/2010 1:33:39 PM, and need to be updated. If they are not updated, the system may stop working. The account is used by the following: Farm Account Microsoft SharePoint Foundation User Code Service User Profile Synchronization Service Web Analytics Data Processing Service Security Token Service Application Application Discovery and Load Balancer Service Application]

I assume updatefarmcredentials will fix this. I tried the following:

stsadm.exe -o updatefarmcredentials -username sysaccountname -password pwvaluehere -local

This results in a "command line error". What is the proper syntax?

You can also just change the current System Account password in AD or Computer Management, and mark it to not expire.

When it comes to the stsadm command, it is userlogin not username, unless that changed in 2010. (Source)