What is the next step in the boot process after the BIOS boots the computer using the first drive that contains a valid boot sector?

After the BIOS identifies and boots the computer using the first drive that contains a valid boot sector, the next step is to execute the boot sector code. This crucial process involves handing over control to the Windows Boot Manager. The boot sector code is responsible for loading the operating system, as it contains the necessary instructions for the system to initiate the boot process effectively.

The Windows Boot Manager plays a key role once the control is transferred to it. It manages the booting of Windows operating systems, allowing the system to start properly and providing options for different operating systems if multiple ones are installed.

The other options represent different stages or actions in the overall boot process, but they do not immediately follow the execution of the boot sector code. For instance, a POST (Power-On Self-Test) check takes place before the BIOS boots the operating system and is not relevant at this moment in the sequence. The Windows welcome screen and driver installation happen after the operating system has begun loading and is not part of the direct transition from the boot sector execution.