Nevermind...
Select Top 1000000 dbo.tblComputers.Computer, dbo.tblComputers.Username From dbo.tblComputers Where dbo.tblComputers.Computername Not In (Select dbo.tblsoftware.ComputerName From dbo.tblsoftware Where dbo.tblsoftware.softwareName = '%Anti-Virus%') Order By dbo.tblComputers.Computer