[Psyke]

There is an issue with sideloaded books (epub books you manually add via ADE or calibre, etc) that, when trying to put the kobo to sleep, actually turns it off instead. Sometimes, it will look like it's frozen, but in reality, it turned itself off, but just didn't go to the power off page.. This is supposed to be fixed with the next firmware patch. If this is happening with Books that you've purchased from Kobo's site and have synced via the desktop software, then you might want to report it to Kobo.

For turning the device back on from an off state, hit the button and look at the light at the top right. As soon as you see it come on, let go of the button. usually it only takes a second or so. When turning it off, hold the button until you get the power off screen (keeping in mind the above sideloaded book problems). When going to sleep and waking it up, just a quick tap should be all that's required.