When attempting to restore a SQL Server 2000 backup on SQL Server 2012 produces the error:
"The database was backed up on a server running version 8.00.0760. That version is incompatible with this server, which is running version 11.00.3128"
1. First migrate from SQL 2000 to a supported version (SQL 2008 for instance).
You need to at least be on SQL 2000 SP4, then follow this step : Migration SQL Server 2000 to SQL Server 2008
2. Make a second migration from SQL Server 2008 to 2012.
This information was sourced from Microsoft TechNet article: Migration SQL Server 2000 to SQL Server 2012