He opened Device Manager. Found the unknown Bluetooth device. Right-clicked → Update driver → Browse my computer → Let me pick from a list → Have Disk.
A warning appeared: "This driver isn't digitally signed." But Leo noticed the timestamp: 2015. And the certificate chain: Qualcomm Atheros. It was signed. Windows was just being paranoid. Atheros Ar5b225 Bluetooth Driver Windows 10 High Quality
Leo had tried everything. He’d rolled back drivers, forced-updated from Windows Update (which offered him a driver from 2009 that made things worse), and even disabled then re-enabled the card in the BIOS. Nothing. He opened Device Manager