I am not sure if you are refering to the BE catalog folder or the data fom a Tape. Assuming you want to restore data from tape and it is not showing up in catalogs, you can right click the Tape and perform catalog on it. Once this job completes, Right Click again and restore out of that media.
If you do not need to keep your jobs, etc, do a fresh install of BE 2012 on your server with the new OS. It would be easier. See this discussion on what to do
If you want to upgrade, then use these documents to help you.