Time Turners

[UNIX4EVR]

No: HPFGUIDX 142241

Excuse me if someone already raised this, but -- 

I know you can't bring someone back from the dead.  We've been told 
this about Harry's parents.

BUT apparently you can go back in time and change events so they 
never happened.  I'm thinking of Buckbeak's execution.  Harry, Ron 
and Hermione used her time turner to go back in time and save 
Buckbeak who HAD been killed.

Get where I'm going with this???

Is is feasible that JKR could have Harry go back in time to warn 
Dumbledore and thus save his life?

Also -- I've gone back and forth on the Snape "good" Snape "bad" bit 
and have concluded he is a rotter.  My reason?  I'm re-reading The 
Goblet of Fire.  Early in the book we are told that Voldemort's most 
faithful servant will return to him and this may allow him to 
succeed.

Harry assumed the servant was Wormtail.  Wormtail isn't that strong.

The faithful servant was Snape.