Probability of winning the lottery, experts only!?

I play lotto 649. Basically its a lottery game where 6 are randomly drawn. There are 49 possible outcomes the numbers 1-49 but everytime you draw one ball out, it cannot be drawn again. I just want to know what is the probability of wining the jackpot by correctly guessing all 6 numbers by guessing 6 times? What about 7 times? Im a noob at statistics and I tried to draw the probability tree to find out but I failed. I hope someone can not only tell me, but show me as well. Thanks!