As it is almost new - i brought it back to the store.
The tech tried it and... surprise surprise it's working well there! (and i'm looking like a fool).
He told me that it could be related to the fact that i'm living in an old house (old connections, old cable, lack of voltage).
It still does not work properly when i plug it in here... (lack of power, buzz sound)
What to do?! (apart moving house :)
Someone ever had that problem?
Thanks,
Edit: Sorry if this isn't posted in the right place!