As per my comment. You can include your username in the remote URL (similar to FTP).
Example without password (SSH):
git remote set-url origin git@github.com/username/repo.git
Example with password (https)
https://name:password@github.com/username/repo.git
Source: Git push requires username and password
Updated 5/14/2018 to correct github.org to github.com in the original answer
Check that Windows does not have a pending update. If it does, update and restart.