Check out the error logs from Event Viewer snap-in console.
Open Event Viewer by clicking the Start button , clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Event Viewer.
View Event ID 1 and 42 for Wake and Sleep.
"They are Event 1 and Event 42 (wake and sleep, respectively).
Open the Event Viewer and expand "Windows Logs" then click on the 'System' event log.
Right-click, and then choose "Filter Current Log".
Input the event id 1 and 42 number into input box above the "Task category" input box.
In the "Event sources" window, click the drop-down and put a check-mark beside "Power-Troubleshooter" and "Kernel-Power" and then click OK.
You will see listing of wake & sleep events and look at the the "General" tab at the very bottom for each Event ID 1 for wake events the wake source will be shown it will be display at the "Wake Source: " entry.
Repair any damage Windows system files by typing Sfc /Scannow command into Command Prompt that is open with administrative privileges.
Report back here with Sfc command scan and repair finish output result.
Click here to update all device drivers on your Windows PC
Windows Power Troubleshooter tool, and see if it is able to diagnose and fix your problem automatically. Open Control Panel --> Troubleshooting --> System and Security --> Power.
Start Windows in Clean Boot State and see if problem disappears. If so then some program or process is interfering with resumption from Sleep. Try to identify the process.
Try different monitor or connect computer to TV set to see if issue is cause by monitor.