https://www.simple-talk.com/sql/backup-and-recovery/the-sql-server-instance-that-will-not-start/
p.s. OS error 5 is Permission Denied. SQL doesn't have permissions to access the new location.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability