The operating system should be removed if you are going to install a new one instead, or if you have two of them on your computer, and one of them turned out to be unnecessary. Otherwise, you risk losing all your data without getting anything in return.
Instructions
Step 1
If you have two operating systems installed, and at some point you suddenly realized that you can easily get by with one, then all you need to do is format the hard disk partition on which the unwanted system is installed. This can be done using Windows tools: find the desired section in Explorer and right-click on it and select the "Format" command. You can use third-party software to work with disk partitions, and format using Partition Magic, Acronis Disc Director Suite, etc.
Step 2
If you need to remove the current operating system, then you should do this if you want to install a new one instead. In this case, restart your computer and enter BIOS while holding the Delete key while booting (or F2, F3, F10, Esc). Install boot from disk by choosing First Boot Device to CD-ROM (or DVD-ROM) and restarting your computer to start installing the new operating system. In the process, you will be prompted to format the system partition, and it is this procedure that will remove the old operating system.
