change SQL service account

 I am trying to change SQL server agent account in my developer machine from local system to my own user name. (this is for a test)

I tried to change it in SQL server configuration manager, but get an error

The specified network password is not correct
and I followed the correct way of doing this in article:

using browse to search in domain instead of typing it manually, http://www.sqldbadiaries.com/2010/12/13/change-service-account-password-the-specified-network-password-is-not-correct/

But still get the same error.

This is a windows 7 box.

SQLFriend