Export / Import Putty All Settings :

Open cmd.exe (Command prompt). Execute below command in command prompt

regedit /e "%USERPROFILE%\Desktop\putty.reg" HKEY_CURRENT_USER\Software\SimonTatham

In Desktop you will see putty.reg (Exported)

To Import putty settings

Double-click on the *.reg file and accept the import.

Or from command prompt execute below command : 

regedit /i putty.reg

https://stackoverflow.com/questions/13023920/how-to-export-putty-sessions-list