Why don't people vote?

Why don't people vote was the question posed in class this week. I large reason I feel that people don't vote is because they still believe it will not make a difference, and in many cases, my case of living in South Dakota, I don't feel me voting makes a difference. Given the fact that our "progressive country" (bullllshit) still uses an ancient out-dated system known as the electoral college, which gives the great state of SD 3 electoral votes. The president is not elected by a direct vote!! How does this make sense!?! That is a downer to both republicans (the uneducated) and the democrats (educated) public.
I consider myslef a more moderate liberal so SD's wonderful history of voting for a republican president every year since 1964, really doesn't interest me in wasting my time to go to the ballot box. 3 electoral votes!! The presidential hopeful doesn't give a rats ass about winning SD, why would he!! 3 Votes will make no difference, you'll never hear Wolf Blitzer say: "It's a tight race here folks, it's neck and neck, coming down to that last state, the next US President will be decided by the people of South Dakota."
That though is only for South Dakota, which has a fair share of people turning out to vote for republicans, or I mean for elections. Other states I feel don't do enough to get people informed and registered, along with many polling offices being difficult to either get to or get to in a certain amount of time. I remember reading about former US representative Charlie Wilson winning elections by giving rides to the poor rural people who didn't have cars to get them registered then picking them up on election day and driving them to the polls. Thats genius, I'm not that familiar with his politics or what, if anything he did to help the poor that elected him but he got people to vote!!