Vik,

sp_attach_single_file_db will work if database was cleanly shutdown i.e. it was detached.

As per BOL

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Remarks

When sp_attach_single_file_db attaches the database to the server, it builds a new log file and performs additional cleanup work to remove replication from the newly attached database.

Used sp_attach_single_file_db only on databases that were previously detached from the server using an explicit sp_detach_db operation.

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OS error 2 = The system cannot find the file specified.

Few questions:

what is the syntax you are using?

As per BOL (SQL 2005)

FOR ATTACH_REBUILD_LOG requires the following:

• A clean shutdown of the database.
• All data files (MDF and NDF) must be available.

HTH