Why he is still alive?

[Marleen]

No: HPFGUIDX 110293

Melody:
>>  I think Dumbledore has not killed Voldie because it would accomplish
  nothing really...yet.  Much like Dumbledore had to have the Minister
  of Magic physically see Voldemort and be forced to admit he exists in
  OoP, Dumbledore realizes that if the WW does not recognize that
  Voldemort is back as a bigger, badder, and more pissed off Voldie,
  then just killing him accomplishes *nothing*.  They need to get over
  the fear or the name, which would still be around even after his
  death.  <snip> <<


I think it makes sense. The WW hasn't even acknowledged that Voldemort 
has returned. If DD had killed Voldemort when he had the chance, then 
Fudge, as you said, would not have realized Voldemort was back. The MoM 
would still think DD and Harry were making the whole thing up. The timimg 
just wasn't right and JKR has more writing to do. We're not letting her 
get off that easy!!! LOL

"Marleen"