I tried DVI dual link, DVI, HDMI, HDMI>DVI, RGB cables and inputs. All had the same issue. Happened on different graphics cards (gtx 670's sli and gtx 570) as well and my other monitors work just fine with the same cables.
The only thing that kind of worked for me was as soon as I saw any...
Same thing over here. I emailed the seller and he asked me to verify a few steps regarding resolution and cables and then said they'd email me a return label. After 3 days and no email I started an ebay dispute and within 2 hrs (on sunday) I received the return label in an email from the seller...
Strangest thing...I bought this same monitor from Ebay...and from the same seller...and I'm having the SAME issues. Terrible horizontal noise that starts after the monitor has been on for about 5mins. Gets worse and worse until the screen goes black. I've contacted the Ebay seller as well. Ugh.