Have an intermittent issue (Windows 8/Dell Inspiron 660s) where PC will not sleep per the sleep timer contained in Power Options. When I open an elevated PowerShell cmd window and run 'powercfg /energy' I get an error indicating the following:

PS C:\Windows\system32> POWERCFG /ENERGY "energy.html" The Power Efficiency Diagnostic library (energy.dll) could not be loaded.

Think the energy report will be key in determining what is preventing sleep mode. I am able to manually put it to sleep, but the issue is related to sleep timer in plan

The system file checker utility, Sfc.exe, allows administrators to scan all protected resources to verify their versions.

Files critical to restart Windows that do not match the expected Windows version may be replaced with the correct versions. If a file is repaired, the corresponding registry data is also repaired. Protected files not critical to restart Windows are not repaired.

Open an elevated command prompt. To do this, press Windows Key + Q, type CMD in the search box and right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.

At the command prompt, type the following command, and then press ENTER:

sfc /scannow

The sfc /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft Versions.