thank you so much for those nice and informative advice. I never would have realized or known things like that do happen in the world of work. Surely, I am new and have a lot more to experience. Well, just a brief review for this week.
I and a friend of mine was walking down the mall on lunch time, and to our great surprise, what did we find? There was this guy with another girl having lunch. At first, I was so shy and reluctant to go over there, but then my friend said, do you want to shut his mouth. He first went and then, well i followed as if I knew nothing of them being there. We went there and he was surprised to see both of us. Now, he has distant himself a little though sometimes he comes and talks but the Facebook chatting has stopped abruptly to my relief :))
I think that now maybe I will be left alone and things will be back to normal.
Well, I still keep my distance and to show him that I am not at all interested in such kind of people.
Thank you very much friends :))

DreamyHope, the world of work can be a confusing one for me, and I think for many, and it is a separate world from ours. I hope you find your niche in your working world.
Your statement about being left alone and things back to normal rings true, at work we just want to do our thing and not be thrown into other dramas.

We have to distance ourselves from things or people that are into other agendas besides getting the job done.

I think the advice above to tell him that you are there to work, is good. You can say that you are there for one thing only-to work and that is all you are focusing on.
Good luck to you in your job!

let me get this right you were not only working together but you was on facebook together as well...?

in fact, it was during the first week. Ignorant that this might end up as such. During the first week, he was so supportive and very friendly. Moreover, he was in the same team, not promoted yet. He has been very nice and made me feel good in the team as I was new. So, i thought of him to be a good person, well he is, but now a little clingy. After did I know about his little tricks.
I did not want to act ill-mannered by not accepting his friend request as some of the other persons added me too. Well, i added him and he chatted a few times but he was still nice in his conversation. I did not let the conversation go too long, so he is still as if a stranger to me. Actually, we never shared any personal details except some work related stuffs. I tried playing that to my advantage. But, I know that at the back of his mind, he wants something to happen, but as I said as we caught him red-handed, he might stop whatever he was trying to do.
His friend request was a week after I joined the office. Did I make a mistake in here? But how could I deny his request since I was to meet him everyday and he would have maybe asked me as to why I haven't accepted and so on, I know I could come up with some excuses, but maybe it should not sound nice on my part. And then, I quite innocently accepted the request.

Hope, I can see how the Facebook thing could be awkward. I am lucky that my work doesn't go in for 'friending' each other on FB, I have friended 2 people from work but only after I knew and liked them as friends, I have not been socially pressured to do so. It is a difficult situation and I don't know what the right answer is.

You say he is a stranger to you and you did not share personal details. That depends on what is on your facebook page. Some people put their workplace, home town (and pics of their home and area so a local could figure the street if not the house where they lived), date of birth, school and college details, where they go and what they do and who with, details of all their family and what relationship each have to them, tagging them in photos so people know exactly who they all are. Maybe you are more careful than that and you regularly check the privacy settings so even your friends cannot see certain things. But potentially he could get a massive amount of personal information about you from Facebook.

If I were you I would go into the privacy settings and make sure you are happy with the way they are set and what he and everyone else can see. If you have previously posted something and it is private you may be able to edit or delete it or control it so he cannot see it.

Maybe I came on too strongly before, it may not be the best plan to storm in all guns blazing shouting harassment. I was just stunned that several people's responses were essentially to play along and make up lies and treat the whole thing as a joke when it is clearly making you unhappy. The best thing is to always be professional online and in person. If he does or says something to make you uncomfortable say politely 'please don't do that'. Don't be alone with him if you can help it, always be somewhere with others. Remember you don't have to do anything you aren't happy with. Keep FB chatting professional too and public if possible, try to limit it to just posting things on each other's walls. If something online makes you uncomfortable save or print it if you can. You can also note down details of face to face stuff he does, but stuff in writing is better as it isn't just his word against yours. I would join a trade union if there is one anyway.