Oh No! all my SSIS packages in MSDB have disappeared!!

In the registry the path to the SSIS config file can be overwritten.

To fix, reset this registry-key (the default for SQL 2005 on Windows 2008 is “C:Program FilesMicrosoft SQL Server90DTSBinn”) …

 [HKEY_LOCAL_MACHINESOFTWAREMicrosoftMSDTSServiceConfigFile]