Why don't Christians follow the Old Testament?

If you can throw out one whole part of the bible, why not the whole thing? And why are so many different versions of it? I mean, why isn't the Old Testament followed? If it's because it was decided that it didn't apply anymore, then why does the rest of the bible apply? It makes no sense to me how one... show more If you can throw out one whole part of the bible, why not the whole thing? And why are so many different versions of it? I mean, why isn't the Old Testament followed? If it's because it was decided that it didn't apply anymore, then why does the rest of the bible apply? It makes no sense to me how one can say, "this part of the bible is wrong, but the rest of it is right." Know what I mean, or at least see why I'm asking?

****note this is an actual question, I really don't know the answer to this. I'm trying to be nice so please don't tell me I'm overgeneralizing or being a b****, just answer the question.
Update: @Gnostic, where did it say anywhere in my question that I wanted Christians to practice the Old Testament? Did you read the question? I asked for answers not for rudeness, thank you. @The Real lololol is that really in the New Testament? some people are saying they just took out the parts they didn't... show more @Gnostic, where did it say anywhere in my question that I wanted Christians to practice the Old Testament? Did you read the question? I asked for answers not for rudeness, thank you.

@The Real lololol is that really in the New Testament? some people are saying they just took out the parts they didn't like...if that's the case can't we take the parts out of the new Testament that we don't like since the times have changed? (i.e. homosexuality)

But the bible says that because Jesus died on the cross, he said the OT no longer applied? Is that the reasoning?

Seriously just asking, no animosity here, I'm just curious to know, so I know what I'm talking about in a debate about something sometime. I like to learn from everybody :D
Update 2: @Jaury, thanks, that's the only real answer I've gotten here, as far as the Christian belief. I myself am not Christian, but I was just kind of wondering why that was.
Update 3: @Song thanks!
16 answers 16