I just came across a blog which linked my SRM in a box document. It was started a few days ago and is called:
Browsing around i found an excelent post about how to recover your root account in ESX.
Some times i come around customers and they installed ESX a long time ago and can’t remember the password. Or they only manage esx with vCenter with the administrator password so they forget the root password.
I suggest you print this one in pdf format and carry it along with you, just in case you might need this!
You can find this post here: http://lewaness.wordpress.com/2009/01/06/esx-35-server-lost-root-password-reset/