When ssh-ing using putty, I sometimes mistype my username, and hit Enter before I realise my mistake. Once prompted for a password, is there a way to go back and re-enter my username rather than having to close the console and open a new one?
You can right click on the title bar of putty and select "Duplicate Session". This opens up a new window with the same settings, letting you re-enter a username and password. This works assuming that you did not specify a user name in the putty host name configuration (using just the hostname instead of user@hostname). This might not be exactly what your looking for but it's better than re-opening and setting up putty from scratch.
My current keyboard-only method for this, using Putty Connection Manager:
Ctrl+U: Duplicate session Ctrl+Shift+Tab: Back to tab with incorrect username Ctrl+D: Close tab with incorrect username Ctrl+Tab: Back to new tab, re-enter username
The Simple way would be to enter Ctrl+C which would close the session. Then right click and restart the session.
The advantage on this would be that you don't need to open a duplicate session / window.