Windows E-mail

Locations of e-mail files:

Outlook Express 6, 7, 8 (XP)
C:\Documents and Settings\Username\Local Settings\Application Data\Identities\{C61C83FA-AC51-41D9-91F1-5A030BB8D5A6}\Microsoft\Outlook Express

Windows Mail (Vista)
C:\Users\Username\AppData\Local\Microsoft\Windows Mail\Local Folders

Windows Live Mail 2011 (Win 7)
part of Windows Live Essentials 2011 (not included with Win 7, free download from Microsoft)