Tried different HDMI ports, a different HDMI cable, and different HDMI signal source? And, of course, manually changing any signal/source select options the OSD might offer?
If the thing is apparently detecting stuff being plugged/unplugged in other ports then maybe check through them all - confirm there's no bent or broken pins, no jammed sensors/parts, no debris bridging electrical contacts, etc. The problem could be as simple as a bit of conductive packaging stuffed into your USB port.
If the product does appear defective and you "just bought" it then you should still be able to get an exchange or refund through the vendor.
Otherwise you'll have to go through ASUS and apply for an RMA ticket. This would be my last option, I hate shipping and delays and hidden costs and approval processes, etc.
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[/Korth]
