See this example (replace the name of the software)
this shows all computers without 'Microsoft Outlook 2002'
Select tblComputers.Computername, tblComputers.ComputerUnique,
tblComputers.Domain
From tblComputers
Where tblComputers.Computername Not In (Select tblsoftware.ComputerName
From tblsoftware Where tblsoftware.softwareName = 'microsoft outlook 2002')