Screensaver, monitor and PC standby issues.

All of a sudden, my PC refuses to:

1) run screensaver automatically
2) put the monitor to standby (timer now set to 1 minute for testing purposes)
3) enter S3 sleep mode (timer now set to 1 minute for testing purposes)

Manually running the screensaver or putting the PC to sleep works fine. I've seen a lot of reports of this happening, and I've tried many thing already:

Nothing is showing for powercfg.exe - requests.

powercfg.exe -energy shows a bunch of "USB Suspend:USB Device not Entering Suspend" errors, but this is also the case on another PC that has no issues with entering sleep, so I am disregarding this for now.

One interesting error, not showing on the other PC, is this one:

Platform Power Management Capabilities:PCI Express Active-State Power Management (ASPM) Disabled
PCI Express Active-State Power Management (ASPM) has been disabled due to a known incompatibility with the hardware in this computer.

But it gets me nowhere. Any ideas before I re-image the OS to a backup from last week, when sleep worked automatically and without issues?

Edit:

Also, these 3 other warnings may be of interest. Mind you, I don't have any wireless network adapter in my PC and I've just turned off my bluetooth dongle but the 802.11 error is still there:

Platform Timer Resolution:Platform Timer Resolution
The default platform timer resolution is 15.6ms (15625000ns) and should be used whenever the system is idle. If the timer resolution is increased, processor power management technologies may not be effective. The timer resolution may be increased due to multimedia playback or graphical animations.


Current Timer Resolution (100ns units) 100000
Maximum Timer Period (100ns units) 156001


Platform Timer Resolution:Outstanding Timer Request
A program or service has requested a timer resolution smaller than the platform maximum timer resolution.
Requested Period 100000 Requesting Process ID 1352 Requesting Process Path \Device\HarddiskVolume2\Windows\System32\svchost.exe



Power Policy:802.11 Radio Power Policy is Maximum Performance (Plugged In)
The current power policy for 802.11-compatible wireless network adapters is not configured to use low-power modes.

But I guess none of the errors/warnings explain why not even my fricking monitor is able to enter sleep....

Re-imaging to a previous state did not help, so I take it this is somehow a hardware issue. Gonna try another GPU card next...

Using another GPU did not help either. One thing I noticed though - why is the "Sleep after" setting on the main screen of my selected power plan not available, when AMD GPU driver is uninstalled? The only available setting is "Turn off display after" but this does not seem to work, same as before on my original GPU. I will now install the GPU driver and see if it starts working... highly doubt it though.

Ok, this is officially the stupidest issue I've ever come across, in all my years (10+) of PC repair tech. Nothing I've tried works. I give up.

O I've finally made progress! By way of elimination, I've found that the culprit is my Logitech F310 gamepad - as soon as I unplug it from the system, the case of insomnia is cured. How can it go from working properly one day, and causing this sort of issue the next?

Anyway I hope somebody may find this info useful, some day.