Explanations please

[Kazza mazzoo]

No: HPFGUIDX 8142

hi,

First off, on the msg line some say RE, some say SV.  What does SV 
stand for??

Second of all, can anyone explain in PoA how Harry stops the
dementors 
the first time round before he goes back in time with Hermione? 
First 
he thought it was his dad, but when he goes back he finds out it was 
himself, and stops them .. .but how did he manage it the first time.  
I think I have a bad case of Back To The Future here lol.  It's like 
round robin, without the start!  Does anyone know?

Oh and a big shout out to Neil!  Hi-de-ho neighbour =)  Nice to meet 
you, and great rendition of Olivia Newton-John mate lol.  Are you on 
Yahoo at all?  

Thanks for your help folks, and sorry if it's a weird one.

Kazza