OOP :Sorting and LV

[steffy07]

No: HPFGUIDX 63585

I just recently joined this wonderful sight, and this is only my
second post, so forgive me if this has been discussed at great lengths
before, but, if LV is a half-blood, why is he in Slytherin house? 
Isn't Slytherin reserved for pure-bloods only?  I know he hats
half-bloods (even though he is one) because he states in CoS that he
wasnt' going to keep that Muggle name, but still, shouldn't he have
been put in another house according to what the Sorting Hat sings
every year?

And by the way, I must say that in OOP, Neville is fantastic.  He
proves  beyond a shadow of a doubt why the Sorting Hat put him in
Gryffindor.

Stephanie