I think I may have had Vista loaded when HC first spun up on my old laptop, but getting it all running via Linux made stuff so much easier. And then I replaced all my hardware over the last two years.
When the launcher was released, all I wound up doing was installing this, and then just copying over the client side stuff like costumes, etc...
As an aside, I nuked my install once with Mids somehow, but other than losing some popmenus I hadn't backed up, it was easy to restore.