i bought an acer aspire e1-531 with windows 8 that needed to be activated. I decided for format it and install windows 7 but all the partitions cannot install windows as they are GPT. The problem is i had already deleted everything on the laptop including windows8 so now my laptop wont switch on unless theres a windows 7 disk in the dvd rom. How do i change the partitions to NTFS when i cant even log on? Need to use windows 7 soon. Help