* What specific laptop model and operating system?
* List all of the video out ports on the laptop.
* Did you test the U2715H's on another computer?
* Did you test with the U2715H USB upstream cable NOT connected to the laptop?
* Was the laptop in some sleep state when you reconnected it to the U2715H?
* If the laptop is off, not in sleep or hibernate, then connected to the U2715H, then turned on, does it work?