Yeah I totally reinstalled windows and bought a brand new pc just to beat Diablo in nightmare mode..
Worked quite well and i'm now level 70, paragon 2210.

Guess I was too slow, but now Diablo has all the buffs in the world. Behemoth, Haste, Vampiric. I'm playing a sorcerer level 35 on Nightmare difficulty.. Diablo kills me almost instantly. I dps maybe 1/10th of his life before dying. Is there any tips on beating him when he has all these buffs on him...