This article explains how to take a backup of a Cisco device using the putty terminal emulation program. You can download putty from here
Open putty as administrator.
Connect a console cable to your PC and connect via Putty to the Cisco device. Make sure you enable session logging (this output is sent to a text file and makes your backup).
Enter enable mode “en” and enter the command “terminal length 0”
Then issue the command “sh run”
Once the output from the above command has finished displaying you should have a text file on the desktop (called cisco-backup in this example).
You can open this in notepad and view the configuration. This text file is your backup.