Your IM archive files are stored on your own PC's hard disk, not on Yahoo's server. So if your disk has been "erased" they have probably gone for good. However, much depends upon the thoroughness of the "erasure" process. Was all data simply deleted without a re-format? Was the disk re-formatted? If it was re-formatted, was every byte over-written? The answers to these questions will determine the chance of getting any of your archive files back. It's probably a job for a data recovery specialist.

By the way, from the way you speak about your emails I assume that you are accessing them on the Yahoo server, and so these were not lost along with your IM files. If this is the case, please take note of the many reports here of people losing their data stored only on Yahoo servers, and back it all up locally, either to hard drive or CD. Otherwise you may one day join the long queue of people who have left it up to Yahoo and lost everything.

Good luck.

thain