Are you saying Trend Micro came pre-installed on your Asus? If so it may be time limited in which case you may have to start paying for it soon.
If you have Avira (free version) go with that - it appears to be liked by many on this forum.
You don't need 2 AV programs - they will just conflict. Some people do however - just as long as they are not running at the same time or in real time protection mode.
I can't advise on either for you - it is a matter of personal choice.