How to Change operating system?

To change the operating system from Parrot OS to Windows OS on your HP EliteBook 840 G2, you will need to do the following steps:

• Backup your important data from Parrot OS to an external storage device, such as a USB flash drive or an external hard drive.
• Create a Windows installation media using another computer. You can use a USB flash drive or a DVD to create the media. You can download the Windows ISO file from Microsoft’s website and use a tool like [Rufus] or [Windows USB/DVD Download Tool] to create the bootable media.
• Insert the Windows installation media into your HP EliteBook 840 G2 and restart the computer. Press Esc to enter the Startup Menu and then press F9 to enter the Boot Options Menu. Select your installation media from the list and press Enter.
• Follow the instructions on the screen to install Windows on your computer. You will need to choose a language, a keyboard layout, and a license agreement. You will also need to select a partition where you want to install Windows. Since you want to replace Parrot OS with Windows, you will need to delete the existing partitions that contain Parrot OS and create a new partition for Windows. You can use the Diskpart command-line tool to do this, as explained in [this guide]. Alternatively, you can use the graphical interface of the Windows setup to delete and create partitions, as shown in [this guide].
• Once you have installed Windows, you will need to activate it using a product key. You can either enter the product key during the installation process or after you boot into Windows for the first time. You can find your product key on a sticker on your computer or in an email from Microsoft if you bought Windows online.
• After activating Windows, you will need to install the drivers for your HP EliteBook 840 G2. You can download the drivers from [HP’s website] and install them manually or use [HP Support Assistant] to automatically find and install the drivers for you.
• Restore your data from your external storage device to your Windows computer.

I hope this helps you change your operating system successfully. If you have any questions or issues, please let me know. 😊