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I have Xubuntu 14.04 installed on my computer and I have 3 partitions in it. /boot, /sda1 (main, 900gb), and /swap (for swap space). I've been trying to install Windows 7 Ultimate 64-bit by following the insturctions here: https://askubuntu.com/questions/6317/how-can-i-install-windows-after-ive-installed-ubuntu (Peachy's answer)

What I did was I shrunk /sda1 to 700gb and created a new partition, NTFS formatted, that can hold 200gb for my Windows installation using GParted live (USB boot). It went smoothly.

After all this, I logged in to my (no GRUB, weird) Xubuntu just to check if it still works. It does

Now, I had an .iso file of Windows 7 and I burnt it into my DVD+RW CD at the slowest speed possible. It was successful as well.

Now here comes the weird part. I restarted my computer and opened up the BIOS to make CD booting the first priority... however, there was no options for CD booting! Weird! So I googled the problem and I saw an article that said that I should have CSM enabled. So I did. After the next restart, I was able to boot using the CD and the Windows 7 installer setup popped up on my screen.

Finally! Right? No. I tried installing Windows 7 on the unallocated space and it said: Windows cannot be installed to this disk, the selected disk is of the GPT partition style. Some articles said to disable CSM so that I can install Windows but if I do then, then I won't be able to boot my CD!

I'm not really sure where to go from here. Some articles talk more about BIOS and UEFI which I really don't understand that much.

It was easy for me before to install a Linux OS when Windows is already installed but the other way around seems too difficult.

My laptop is an ASUS X550LB if that helps.

mpmp
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1 Answers1

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To use GPT, your Windows must boot in (U)EFI mode.

Normally Windows install DVDs are dual-boot (both legacy BIOS and EFI supported).

When you set you boot device to DVD, your BIOS starts with legacy boot method (red book).

But if BIOS finds that DVD is UEFI-bootable, it should add another entry to boot menu that will allow this.

To boot with (U)EFI, you should first enable it in BIOS, and then to select UEFI DVD boot menu item (it will be separate from legacy "DVD-ROM" boot item).

Also there is question with answer how to boot EFI entries, if they're not listed (on another ASUS notebook): If USB is not listed in BIOS as a boot option, does that mean the machine can't boot from USB?

LogicDaemon
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