Depending on where you find it, the "simulator" can mean several different things:
You are a user who has just triggered a critical system exception. But as the dreaded :( appears, the screen glitches—and you find yourself standing inside a fragmented Windows desktop that stretches to infinity in all directions. Windows Infinity Simulator
Programming Projects: Platforms like Tynker host user-created coding projects where students build their own "Windows Infinity" desktop environments with functional buttons and custom wallpapers. Common Features in the Simulators Depending on where you find it, the "simulator"
Many modern YouTube horror creators have combined the two. There is a famous analog horror series titled "I found the Backrooms inside a Windows 98 Virtual Machine" that relies entirely on Infinity Simulator logic. Depending on where you find it