It’s impossible to erase the hard drive or uninstall Windows while using the operating system. you can’t erase the hard drive on your C drive when you’re booted into Windows.
If it is, you may need to enter your computer’s UEFI settings menu to boot into it. Go back to the main menu, then select Troubleshoot, Advanced Options, and UEFI Firmware settings Once you’re in the UEFI menu, use the keyboard (or mouse if you get a graphical menu) to navigate to a boot menu and select your device if it’s there. If it isn’t, plug the installation back in and go through the same process above to enter your UEFI menu and try to boot into it.
If you entered a full screen menu, you will need to navigate over to a boot menu. If the menu you see on your screen is mainly blue and white, you’ll need to navigate using your keyboard. If the menu is graphical, you can use your mouse. Once there, you should see the installation media listed there. If it isn’t there, something might have gone wrong. If you pressed the button to open the Boot Menu, you should already see a list of bootable devices. Navigate to the installation media. Boot into it.
If you want to do a complete clean install, delete all the partitions in the drive that are visible, until it’s all unallocated space.
If your Mac has a single internal disk, click Restore. If your Mac has multiple internal disks, select the one that has Windows on it, select Restore disk to a single macOS partition, then click Continue.
