Log File over 400gigs...need to bring this database back to life
It sounds like no one took log backups on that database for a very long time.  Restore the MDF and try:

EXEC sp_attach_single_file_db @dbname='YourDB',
@physname=N'C:\Path\To\YourDb.mdf'
GO


Then set up regular backups for those databases, both full and log backups.  This is an article on log backups that might help.  This is a more general article on SQL Server backups.

Good luck!