EDB is the normal default storage for Windows Live mail. It does not, as has been pointed out three times in this thread, use the username - Contact, folder."
Yana. The thread is suffering from some contradictions, I'm afraid. But if you have got an EDB (contacts ) file from Vista, why not copy and paste it to its live mail Folder in Windows 7?
The path is
D:\Users\usernamer\AppData\Local\Microsoft\Windows Live\Contacts
You will see another EDB file there. As a precaution, just copy it somewhere safe, so that you may return it if needed.