Does it still happen if you set your system clock to the wrong time? That would tell you if it's scheduled on your PC or another device on the network that may be doing this.
Yeah, I've tried that before several times. Nothing changed.
Might be controlled remotely, it could possibly be a RAT, especially as you even change the system clock, and if the Ethernet cable is unplugged nothing happens.
Have you tried connecting to the internet via wireless internet connection?
No, I have not. But I'm not entirely certain this machine has wireless capability.
EDIT: Ah, no, it doesn't have a wireless network adapter.
Not as far as I know.
EDIT:
No luck, I'm afraid.
Yeah, I've tried that before several times. Nothing changed.
Have you checked scheduled tasks?
Outside of that.... I really can't say. What you are describing really makes no sense.
I know, I've never heard of anything like it before.
No, I have not. But I'm not entirely certain this machine has wireless capability.
EDIT: Ah, no, it doesn't have a wireless network adapter.
Nope, no wireless capability whatsoever.
Start Explorer.exe "%Appdata%\Microsoft\Windows\Start Menu\Programs\Startup"