AutoComplete, User Names and Passwords on Forms:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\IntelliForms\SPW
AutoComplete, Web Addresses:
HKEY_LOCAL_MACHINE\Software\Microsoft\Protected Storage System
Provider\<user name or windows logon name>
Note that the user names & passwords are store at HKCU & thus you'd need to save for each user account (having logged in at each).
You should be able to Export & save those keys. But I do not have direct knowledge if an Import (later on) would go ok. It should.