Operation aborted (Exception from HRESULT: 0x80004004 (E_ABORT)) sharepoint

Suddenly my sharepoint site showing this error "Operation aborted (Exception from HRESULT: 0x80004004 (E_ABORT)) "

I am running my site on MOSS 2007 (version 12.0.6425.1000) and SQL server 2008 R2.

I was getting a similar error but running SharePoint 2007 on Windows Server 2003 SP2 with SQL 2005 as the database. This is an organisation environment where all users access SharePoint intranet via the domain so I gave access to the NT AUTHORITY\NETWORK SERVICE account access as a db_owner to the SharePoint content database, Search database and that eliminated the error.