Most Windows 8 base PC such as HP Envy 15 notebook require BIOS/UEFI setup before you can downgrade it to Windows 7. Before we start I would like to point out important points: For this tutorial : We use Internal DVD/CD- ROM as install disk. (change it base on your boot disk such as flash drive or external DVD/CD-ROM). I strongly recommend to use Windows 7 SP1 because it is more stable and fix some bugs like remove pop-up notification about secure boot. 1.First step We need to access UEFI BIOS, here is how: UEFI Firmware Setting on Windows 8 Press the Windows key + C, or swipe in from the right edge of the screen to open your Charms. Click Settings. Click Change PC Settings. In PC Settings, select General. Scroll down to the bottom and Under Advanced startup, click Restart now. In the boot menu, select Troubleshoot. In the Troubleshoot menu, select Advanced options. In the Advanced options menu, select UEFI Firmware Settings. Click Resta...