Hello, i have a Lenovo y50 i5 gtx960m,8 gb ram,.... back to the point, sometimes, when the laptop is pluged in (dosent matter power plans) some horizontal line apear on scren, at the begining i thought it was some hardware problems...but....i put my ear on my ac adapter (brick) and i heard a frying sound(like when you fry oil in the pan)....it is not the 50hz sound, it is normal for an y50? or i should buy a new one?