To install Windows on a separate partition or hard disk

Before installing Windows, be sure to disable all antivirus software and back up your files to an external hard disk, a CD, a DVD, a USB flash drive, or a network folder.
1. Turn on the computer running your current edition of Windows, and then insert the installation disc into the computer's CD or DVD drive. (You need to be running Windows to perform this procedure; do not restart your computer using the installation disc.)
2. On the Install Windows menu, click Install now.
3. On the Get important updates for installation page, we recommend getting the latest updates to help ensure a successful installation and to help protect your computer against security threats. You must be connected to the Internet to receive installation updates. This page might not appear if your computer is not connected to the Internet.
4. On the Please read the license terms page, if you accept the license terms, click I accept the license terms.
5. On the Which type of installation do you want? page, click Custom.
6. On the Where do you want to install Windows page, select the partition or disk where you want to install the new Windows operating system. Be sure to install Windows on a different partition from the partition where your current version of Windows is installed.
7. Click Next to begin the installation. You might see a compatibility report.