Diablo 2 is not playing. Help, please?

I recently bought Diablo 2 and I installed it on my computer which is a Dell Inspiron 530S running Windows Vista. I put it the play disc but it keeps saying that I have not inserted it. And when I insert the play disc it acts as if that's the install disc. It also warns me when I click on the shortcut that there are compatibility problems. Any help is appreciated, thanks.