SQL Server database goes into suspect mode

You receive the error message in  SQL Server Management Studio

Database 'msdb' cannot be opened. It has been marked SUSPECT by recovery.

1. Stop SQL Server service.
2. Rename or remove old files named MSDBData.mdf, MSDBLog.ldf in directory [SQL Server Instance name]\MSSQL\DATA (exsample C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS2008\MSSQL\DATA).
3. Copy files named MSDBData.mdf, MSDBLog.ldf in [SQL Server Instance name]\MSSQL\Template Data\ (exsample C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS2008\MSSQL\Template Data).
4. Restart SQL Server Service.

Please check the blog below which describes how to repair it.

http://www.sqlservercurry.com/2011/03/repair-sql-server-database-marked-as.html

And the similar threads below:

http://social.msdn.microsoft.com/Forums/en-US/sqldisasterrecovery/thread/d9a8bd3b-017c-4ff9-b26c-71402c70bfe6/

http://social.msdn.microsoft.com/Forums/en-US/sqldatabaseengine/thread/6fce2d35-58db-4e18-81af-8b8987d65323/