Windows.old would not be there. You've apparently done an "Over the Top" install and Windows created a backup, thus the ".old" files. You might try to import the messages, and point to the folder where the .old files are.
I recently reformatted my computer and lost all the E-mail that was stored in Windows Live. I didn't back it up, however when I look in my Windows.old Folder, I can do a search and the messages are still there. So it's all still in the Windows.old, I just have no idea how to access it. Are they all in some kind of System Folder or something? Where can I go to access the E-mail messages?