Downgrade windows 8 to Windows 7 Acer Aspire E1-531 HD

In this video you could see how to fix 1. convert GBT to MBR 2. UEFI to Legacy Bios (for you to boot on DVD) This apply to ACER particularly Aspire E1-531 Downgrade from windows 8 to windows 7 Two Problems I encounter 1. Boot up on DVD (UEFI to legacy Bios) 2. MBT partition style (error installing windows7) need to convert the partition from GBT to MBR for you to install windows 7 UEFI Boot Option Removal/Disable on Windows 8 to install windows 7 in Acer Aspire E1 5