Lenovo A540 All-in-OneĀ  (lenovo) Drivers Operating System: Windows 8.1 x64 (64 bit) Drivers: Audio Realtek Audio driver v6.0.1.7188 Release: 21 Apr 2014 Size: 299 MB Bluetooth and Modem Realtek BT Driver v1.3.805.3 Release: 21 Apr 2014 Size: