Saying NO... nicely :)

Here's the story...

there's a guy who I know who gives me a weird vibe, he's kind of whimpy, nerdy, but also self-absorbed. NOT my type. Let's call him Fred. He asked me out and I said I would be busy for the next few weeks and not available to watch a movie or go out. I thought it was pretty clear that I had no interest.

Then, just a few days later, another guy asks me out kind of spontaneously. Let's call him Tim. I know him better than I know Fred and he's quite nice. I was surprised at him asking me out and kind of thought it was too good to be true. Well, despite our best efforts to go on a date, work and school got in the way and we cancelled twice.

Fred asks me out again. I tell him that I had plans to go out with Tim and it's not a good time for me to go out with Fred. Fred tells me Tim is "probably lame"... I'm telling you, he is obsessed with himself. We parted ways.

Here's the TWIST! Tim continues to talk casually to me, occasionally flirty. But he is seen at the movies with another chick! Total player. Well, feeling slightly let down, the situation with Tim proved to me that I really am not ready to even try dating. He was the first guy I opened myself up to in years and it turned out poorly. I have other and better things to focus on anyway.

So, Fred asks me out again. Seriously. He can't take a hint. I have about 20+ reasons as to why I do not want to go out with him. I'm tired of hinting it because he just doesn't get it. How do I tell him NO, once and for all? I don't want to give him any part of the story, it's just none of his business. Do I say I'm seeing someone? It's complicated? I'm not ready? Help!!