I have a monitor U2713H from 2 weeks (is a Rev A07 July 2014) connected with cable supplied DVI-D.
After some time that it's on vertical lines appear and the OSD menu and power button are locked to turn it off I have to unplug the power cord.
I reinstalled windows 8.1 (64bit) and updated the driver from the Dell website. I also tried changing the video card.
Good troubleshooting. Sounds defective. Contact Dell Italy Technical Support and get it exchanged. For my notes, what is the 20 digit serial number?