alright.....i pulled up a few details that may give us some answers:
Well about the stuff that Voldemort did to make himself inmortal, he didn't actuall sussced all the way, remember? He did alot of stuff but in the end his trasformation only made it half way. That's why he didn't die the night he killed the Potters(and tried to kill Harry)because according to him the "ancient" spell that her mom used when she sacraficed herself for her son had to kill him. He may not be able to be killed completly but he can't stay very powerfull afterwards either. Now this was last time, I don't know if it remains the same this time because he was re-born. But I'm guessing he's mortal again because otherwise Harry wouln't stand a chance, unless something Dumbledore said has to do with this. Remember he told Voldemort that there where worst things than death?
I think when Dumbledore told Volderort there are worse things than death, he meant the diverse ways Voldermort was using to keep alive and keep on going:
1 Living like a parasite living off another
2 drinking unicorn blood
3)preserving himself in an enchanted diary
Voldemort has one main issue that blinds him to all other concerns:
He is afraid of dying and will do anything, no matter how painful or horrible, to survive.