I thought Claire's blood can bring people back from the dead just like it helped Noah when he was shot.Why didn't they use her blood to help the real Nathan instead of erasing Sylar's memories?

WELL i think nathan was already dead so claire couldn't save him plus angela wanted something different i suppose plus vol 4 is going in the direction that 5 years gone had described and nathan was dead in that.

I think it's because Angela Petrelli a dit that Matt Parkmen neede to save Nathan and because they did not want Claire to know posibably that her father is dead. Another reason would be because Claire's blood can regenorate body tissue not brain tissue. And not only that but why not use Slyar's body he's a lot stronger then Nathan and Sylar is gone?

i know its like superstupid but for ratings. sylar is like one of the biggest chahracters so plus people will watch just to see if he comes back. it's stupid executive tv logic :D

cause the writers promised there will be no blood ressurections in season 3!

i think it was because nathan was long dead when angela and matt found him.
and claire's blood can only heal and not bring back the dead.

The death is a proper death, the reincarnation is a set up for the Sylar arc in Season Four. They didn't want to reveal the death to Claire and it got rid of Sylar for them, ou so they believed.

maybe the writers just wanted to be able to bring sylar back suivant season..

I THINK THAT THEY DIDN'T REALLY THINK ABOUT IT LIKE THEY HAD TO MAKE A DECISIOIN RIHGT AT THAT MOMENT AND IT NEVER REALLY CROSSED THEIR MINDS.

I think it is because when HRG was shot, the bullet didn't kill him and he could be rushed to an intensive care room. A bullet to the head doesn't necessarily mean death--whereas a slit throat does.

Because nathan has powers.... Claires blood wont work on fellow heroes.. thats why hiro needs a healer to heal his brain tumor.... so the answer isssss claires blood will not heal other heroes.... :D

Angella Petrelli saw Parkman not Claire "saving" Nathan, and earlier in that episode she a dit to Claire that "I cannot change what I dreamed but I can help push it's outcome" So obviously it had to happen the way she dreamed.

I think it's because Angela saw Matt saving Nathan in her vision not Claire. But her vision was unclear, and who she really saw was Syler as Nathan. And if Claire had've wanted to save him, it would have been to late. Besides, Nathan's death was pretty instantaneous. Whereas Noah, he was shot in the eye. Which wasn't nearly as ..damaging.

The obvious answer is because they wanted to kill off Nathan, not threaten him and then revive him. Within the story, I guess Noah and Angela both forgot that Claire's blood can revive.