Half good and some not good results in a research paper? I have made some research about a computer science topic. The initial idea seemed good, but when I implement the idea; this works in some cases and in some others it does not bring conclusive results.

How can I write a paper about this subject in particular? I mean, I do not want to hide the bad results. I want to include them, but I feel scared that my paper could not get accepted because of that.

I was thinking also to submit it in a not so prestigious conference, but also I do not see any advantage on doing so.
It's important to remember that a paper is supposed to make some kind of contribution. It's not merely a report on "things you did". So if you have some good results and some inconclusive results, what's the contribution ? As sr3u says, you need to work out what's going on and come up with some answers. It's entirely possible that you fail in this endeavour and end up with NO paper. That's not fun, but it's something that you must accept as a possibility.