try this:
SELECT dbo.tblComputers.Computername, dbo.tblSoftware.SoftwarePublisher, dbo.tblSoftware.softwareVersion, dbo.tblSoftware.softwareName,
dbo.tblComputers.Domain, dbo.tblComputers.Userdomain, dbo.tblComputers.Username
FROM dbo.tblSoftware INNER JOIN
dbo.tblComputers ON dbo.tblSoftware.ComputerName = dbo.tblComputers.Computername
WHERE (dbo.tblSoftware.SoftwarePublisher LIKE '%mozilla%')