The PCG-41213W often has an Intel WiFi Link 5100 . Download the last official driver from Intel's archive (version 13.2.1). Do not use Windows Update for this; Windows 10 driver via WU often disables Fn+F2 wifi toggle.
Remember: Windows 8.1 is actually the most stable OS for this model, as Driver Signature Enforcement is less aggressive. Windows 10 works but requires the "Have Disk" workaround for graphics. Never install generic "Driver Updater" software. Sony Vaio Pcg-41213w Drivers
If you have a working set of PCG-41213W drivers, consider uploading them to the Internet Archive to save the next Vaio enthusiast from hours of frustration. The PCG-41213W often has an Intel WiFi Link 5100