SELECT dbo.tblComputers.Computername, dbo.tblComputers.Domain, dbo.tblComputers.Userdomain, dbo.tblComputers.Username,
dbo.tblOperatingsystem.Description, dbo.tblSoftware.Lastchanged, dbo.tblSoftware.softwareName
FROM dbo.tblComputers INNER JOIN
dbo.tblOperatingsystem ON dbo.tblComputers.Computername = dbo.tblOperatingsystem.Computername INNER JOIN
dbo.tblSoftware ON dbo.tblComputers.Computername = dbo.tblSoftware.ComputerName
WHERE (dbo.tblSoftware.softwareName LIKE '%office%')
you should change the '%office%' part