The Base Operating System Management Pack (05.0.3500.0000) released to http://www.microsoft.com/downloads/details.aspx?FamilyID=e553062f-bd85-4772-8037-8b91f457b710&DisplayLang=en a few weeks ago has been temporarily withdrawn due to technical issues currently being investigated. The former version of the Management Pack is available on the link until such time as the MP is re-released.
If you have installed the 05.0.3500.0000 version of the Base OS Management Pack you may observe the following issue when Management Server/s and agent are restarted.
If your management server/s exhibit this problem attempts to start the MOM service manually should succeed either by logging on locally or through the services MMC snap-in remotely.
I will post more information as I receive it.
Clive Eastwood, MOM Supportability Program Manager