Both cmd.exe or PowerShell can be used to export all of the settings of PuTTY. These commands will create a file named putty.reg on your Desktop.

Run cmd.exe as administrator

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

Run PowerShell as administrator

reg export HKCU\Software\SimonTatham ([Environment]::GetFolderPath("Desktop") + "\putty.reg")

IMPORT

The easiest way to import the putty.reg file is simply to just double-click the putty.reg file. Or, cmd.exe or PowerShell can be used to import putty.reg. It is important to recognized that this will overwrite any settings you currently have in PuTTY.

Run cmd.exe as administrator

regedit /i putty-sessions.reg
regedit /i putty.reg

Run PowerShell as administrator

reg import putty-sessions.reg
reg import putty.reg