Complex sentence: Although NANO Antivirus failed to pass the VB100 certification in the first the attempts it has since achieved five VB100 awards, but had failed to reach a pass on the latest test.
Split into simpler sentences: Although NANO Antivirus failed to pass the VB100 certification in the first attempt, but since then it has achieved five VB100 awards. Later, it had failed to reach a pass on the latest test.