Can we remove evil from the world

I was a volunteer at the First GNU/Linux Install Fest in Kerala (first publicly held). The event was a lot of fun and we had a lot of technical discussions. One of my discussions with a volunteer diverted and ended up on a discussion about evil in the society. I am sharing the relevant parts and some of my related thoughts and questions here. We could not discuss much because of the busy schedule at the meet but it had set off a few trains of thought. This is still an idea in the works and this is probably going to be a lot of questions, if not all, than a lot of answers. Also this is probably going to be highly incoherent as some of the chains of ideas were widely separated.

I started Zyxware with a vision to build a business that itself will be able to drive the change I wished to see in the world and also to get me to a position where I would have the financial and operative base required to set off on my own towards this ideal. I am making a few assumptions as foundations for this vision. One is the existence of 'good' and 'bad' and the possibility of a positive change from good and bad. Two is that I would be able to distinguish between them and do what I think is good.

But is there something called an absolute good or an absolute evil? For example can killing a man be called an absolute evil? What if he himself was on a killing spree using a machine gun in a crowded street? Would it then become an absolute good?

For actions where the consequences are not directly evident, how do you know what is good and what is bad? For example, Is giving money to a poor man good? Wouldn't it have been better to invest the money for his children's education?

When you have alternative choices for an action, can we really classify the actions as good and bad? For example, Is distributing a given amount of money to build houses in a village better or worse than using the same amount of money to build a school in the same village? Is giving money for a charitable cause like an orphanage better or worse than giving money for a rural development program?

Can we really know whether the macro and micro consequence of our actions and decisions to be able to classify them or even attempt to classify them? Example - Have the invention of computers made human life better? Do we even know that our lives have become better? Is living longer better than living a shorter life?

What if something that is good for me is not good for others? Would it be good or bad? Say if we take democracy as a means to solve this problem and define that it would be good if it is good for the most number of people, then would it be good if it was good for me and not good for just one another person? What if it was very good for one person and slightly bad for another person?

Humans are not all rational and hence some of them will always do irrational things. So some of them will do evil things. But is evil always irrational? Can't evil be rational? Can it be? People are not all identical. They will perform different actions under identical situations. So there will be variabilities in life. Some of these variations would be what one could classify as 'not good' as there would be some variations that could be classifed as 'good' which have to be different from the 'not good' in some aspects. So there will always be evil.

Some people derive satisfaction in fighting the so called evil. If mankind comes to a stage where all the currently defined evils have been elimated what will happen to such people? What will these people do? They will probably then define something else as evil and then fight against that.