Try this:
Select Top 1000000 dbo.tblComputers.Computername,
dbo.tblComputers.ComputerUnique, dbo.tblComputers.Domain, Web40OSName.OSname,
tblOperatingsystem.Description, dbo.tblComputersystem.Lastchanged,
Web40OSName.Compimage As icon, tblOperatingsystem.Caption,
tblOperatingsystem.OtherTypeDescription
From dbo.tblComputersystem Inner Join
dbo.tblComputers On dbo.tblComputersystem.Computername =
dbo.tblComputers.Computername Inner Join
dbo.web40ActiveComputers On dbo.tblComputers.Computername =
dbo.web40ActiveComputers.Computername Inner Join
Web40OSName On Web40OSName.Computername = dbo.tblComputers.Computername
Inner Join
tblOperatingsystem On dbo.tblComputers.Computername =
tblOperatingsystem.Computername
Where dbo.tblComputersystem.Domainrole > 1
Order By dbo.tblComputers.Computer