Why is this so hard? Because the PCG-81114L suffered from a hardware identity crisis. It used a GMA 500 (Poulsbo) graphics chipset. Intel hated this chipset. They dropped support for it faster than Sony dropped the Vaio brand. There are no official Windows 7 drivers for the GMA 500 from Intel. The only ones that work are custom-stitched drivers from a community of hobbyists on a forum called "Vaio P Enthusiasts," who have modified INF files to force Windows to recognize the GPU.
Enabling the specific Function (Fn) keys, webcam, and SD card readers that often fail to work with "generic" Windows updates. Sony Vaio Pcg-81114l Drivers
Imagine the scene: It is 2:00 AM. You have just installed Windows 7 (because Windows 10 runs like a sloth on tranquilizers on the Atom Z540 processor). Device Manager stares back at you, littered with yellow exclamation marks—a constellation of failure. "PCI Device," "SM Bus Controller," "Unknown Device." Why is this so hard