What happens if you set your system to sleep mode with the screen always on?
If you have an admin account, windows 8 may demand a password regardless of setting after awakening. Perhaps someone else can verify, as I cannot try this myself. Two methods are shown here on how to disable your password if your system goes back to successfully sleeping and asking for a password.
Sleep issues are quite common. I have a new acer aspire laptop, fully updated, and it does not awaken out of sleep or hibernation in windows. I also have windows 7 on an msi system and it does not always awaken when going into sleep mode after the lid is closed. The keyboard does nothing. In my case I believed it was due to either incompatible drivers with the operating system,or a motherboard needing a bios update. For both of my systems it was easiest to just remove both sleep and hiberate from my shutdown options-eg in 8 the acer power option in the taskbar, and metro user profile.