Check whether the Sony AR-770U supports Windows 11 officially
Back up all important files
Download the Windows 11 ISO from Microsoft
Create a bootable USB drive with at least 8 GB capacity
Enter the BIOS or UEFI setup on the Sony AR-770U
Set the USB drive as the first boot device
Enable UEFI mode if available
Enable Secure Boot if available
Enable TPM if available
Save BIOS settings and restart
Boot from the Windows 11 USB drive
Select language, time, and keyboard settings
Click Install Now
Enter a product key or choose I don’t have a product key
Select the Windows 11 edition
Accept the license terms
Choose Custom: Install Windows only
Delete or format the target partition if needed
Select the drive or partition for installation
Click Next to begin installation
Wait for Windows 11 to copy files and restart
Complete the initial setup after reboot
Connect to Wi-Fi or Ethernet
Sign in with a Microsoft account or create a local account if allowed
Install Sony device drivers if available
Run Windows Update
Install chipset, graphics, audio, and network drivers
Check Device Manager for missing drivers
Update BIOS if Sony provides a compatible update
If Windows 11 is not supported, use a supported workaround only if you accept the risks