If your device ID matches any of these, you need the Broadcom 802.11n driver version 11.
But Raj had learned one thing from his engineering courses: old problems had old solutions, hidden in the digital sediment. broadcom 80211n network adapter driver windows 7 64 bit 11
To get your Broadcom 802.11n adapter working on Windows 7 64-bit: If your device ID matches any of these,
Broadcom Wireless LAN Driver (802.11a/b/g ... - Lenovo Support broadcom 80211n network adapter driver windows 7 64 bit 11
: Fully supports IEEE 802.11n (Wi-Fi 4), providing data rates up to 300 Mbps or 600 Mbps (depending on hardware antenna configuration).