This is the needed SQL code:
SELECT TOP 100 PERCENT dbo.tblComputers.Computername AS Computer, dbo.tblOperatingsystem.Description, dbo.tblSoftware.softwareName AS Software,
dbo.tblSoftware.softwareVersion AS Version, dbo.tblSoftware.Lastchanged
FROM dbo.tblSoftware INNER JOIN
dbo.tblComputers ON dbo.tblSoftware.ComputerName = dbo.tblComputers.Computername INNER JOIN
dbo.tblOperatingsystem ON dbo.tblComputers.Computername = dbo.tblOperatingsystem.Computername
WHERE (NOT (dbo.tblSoftware.softwareName IN
(SELECT software
FROM tblapprovedsoftware)))
ORDER BY dbo.tblComputers.Computername