Well, if (for what reason ever) you stopped your SQL-Server, delete a huge transaction logfile of your database (you know, those damn *.ldf files that fill up your hard drive) and tried to restart you server and access your db … you will fail.

Detaching and re-attaching the database won’t do. In this case, try something like this:

USE master;
GO
EXEC sp_attach_single_file_db  @dbname=  '[mydbname]' ,  @physname= 'E:\Database\[mydbname]_Data.mdf';