Dell U2413 Won't power up

Hi guys! I just received my (long awaited) Dell U2413 (rev. A02) monitor. I plugged it in and went about the business of setting it up. While I was setting up, it showed the hovering "No cable- The display will go into Power Save Mode in 5 minutes". I took no notice, as I knew I'm about to plug the input cable soon. And indeed, the display went into PSM, turning off- but then would not turn on! Now, regardless of input (HDMI, DisplayPort, DVI) or source (MacBook Air, PC) it will not power up :( I press the power button, the button lights for 2-3 seconds, but the screen shows nothing, and then the button turns off... I can't even get it to show the On-Screen menu. I tried disconnecting it for several hours, keeping the power button pressed for several seconds while all cables are disconnected, pressing buttons 1+4 as the Troubleshooting guide suggests (although that should only help in self test= hovering message mode)- and nothing. Is there a way to revive the monitor? To reset it manually? Or is my only option having it replaced? I bought it for a big project which is just around the corner, and would *LOVE* to find a way around this... The monitor was working, and presto- unresponsive! Dell people- any suggestions?