Windows 8.1 system sleep can not wake up is going on

Windows 8.1 system sleep can not wake up is going on?
Windows 8.1 is Microsoft's launch of Windows 8 in October 2012, Microsoft began to develop Windows 8 update package. In the project codenamed "Blue", Microsoft will standardize operating system upgrades to provide users with more regular upgrades. Many friends used to use Windows XP, and now there are some minor problems in using this new system.
Below, let's take a look at the system troubleshooting.
Fault phenomenon:
Upgrade Windows 8.1 Can't manually, automatically sleep, or sleep can't wake up, turn off mixed sleep.
Solution:
Control Panel---Hardware and Sound---Power Options---Balance Right Change Plan Settings (or select your own selected mode change)---Change Advanced Power Settings--- Sleep---Allow mixed sleep---Close---Save.