How to transfer chat history or message archive from one computer to another?
1. Exit Yahoo Messenger if you are using it. (Just to be safe)
2. Go to: C:\Program Files\Yahoo!\Messenger\Profiles
3. If you have multiple ids, you can see them there, copy the ones you need and put it on some other folder, like the desktop or the like. Remember to Rename it before saving. If you are planning to backup your Yahoo! Chat History, You too can follow the above steps and copy it back to the same location as before after you reinstall your messenger and windows.
4. If you are using Windows XP, you can paste it back to C:\Program Files\Yahoo!\Messenger\Profiles after you install your messenger.
5. But my problem was that I was using Vista and Yahoo! did not save the archive in the same place in Vista as in XP.
6. In Vista, the location of Yahoo Messenger profiles is C:\Users\xxxx\AppData\Local\VirtualStore\Program Files\Yahoo!\Messenger\Profiles so you need to paste it there for your archive to be visible. xxx is your default document directory.
7. Thats it!