If you are talking about the username and the password to log in to the user interface pages of a Comcast supplied gateway device, you can't change the username of admin. You can only change the password. Go to http://10.0.0.1
Hello, bbanner. Welcome to the Xfinity Forums!
It looks like EG was able to provide some great advice for this issue. Please let me know if you were able to figure it out or if you need further assistance. We would be more than happy to help.
bbanner, as I have not heard back from you in some time, I have closed this thread to further comments. If you still need assistance, please feel free to start a new thread.
The "How to check power levels" video explains it as well: https://youtu.be/cGmKbNGzJKM?t=122