I decided that i needed windows 10 to make my laptop work better. So i asked a friend to install it for me. However i didn't quite like it. So i decided to go back to win 7. I formatted local disc (c) which was the disc that had windows. But when i select this partion to install windows there was an error saying that windows cannot be installed on this disk. I found out that it's all about reformatting hard drive to a different partition style (MBR GPT) . I found a way to do it. However, i have data on local disc (d) . Since i have formatted one that i had so i don't know how to get to a screen where i can select and transfer my files to a external hard drive. Shortly, cannot install windows because of an error and cannot transfer my files because i don't have windows. Is there any way to transfer files without any os? Is there a way to use windows from a external drive (usb drive) ?