things needed:
laptop
external storage with enough free space to hold a backup
Windows 7: Control Panel > Backup and Restore (whole nine yards backed up)
Windows 8: Either Windows 7 File Recovery (backs up everything) or File History
Windows 8.1: File History (backs up just files)
Ubuntu/maybe other distros: Settings/Preferences > Backup
MacOS: idk, look for backup or time machine?
Or, if you just want some specific stuff, go for good ol' copy paste