I am on my second Nexus 7 in 4 weeks. The first one worked fine until the automatic update, then it would not turn on. I took it back to Comet. They replaced it with a new one, after showing me how to reboot it holding down all the buttons. The second one updated about 5 hours after I bought it, and now that too sometimes will not switch on and I have to press all the buttons, then the power button. Has anybody else encountered this problem? I also am having problems screaming videos from a USB stick with NMI. I have tried various video players but playback and audio is very fragmented. Any ideas?