Dual Booting Windows 10 - without it already installed

TacticalFish · 21 May 2016 at 12:06

Hello Folks,

So I've tried searching this without much success, the majority of articles and forum posts go form the angle of dual booting Linux from an existing Windows install.

This would be fine, if I hadn't completely overwritten my HDD with an Ubuntu install.

So, my question is, can I dual boot Ubuntu and Windows 10, from my existing install? Or will I have to install Win10 as the primary, then go through the DB process?

Currently running 12.04 LTS (yes I know I'm behind the times)

Looking at the inbuilt disk utility program, doesn't seem to be the option to do a partition from the existing one.

Any help appreciated.

TacticalFish · 21 May 2016 at 12:13

Damn, ok. I think I've shot myself in the foot here as I've pretty much only got one partition, which is the /boot one.

joeyjojo · 21 May 2016 at 15:42

The disk has a single partition? You should be able to

Boot from live CD
Shrink filesystem with `resize2fs`
Shrink partition with e.g. `gparted`
Make new partition
Install Windows

The tricky bit will be dealing with Windows clobbering the boot sector. I don't know how to deal with that.

mrkev · 21 May 2016 at 20:40

After getting Windows installed you could try something like EasyBCD. Easy to use and works for me with Linux and Windows 10.

memyselfandi · 22 May 2016 at 10:51

Friend on mine was doing this the other day and had all sorts of issues as Windows 10 wanted the disk to use a GPT partition table and UEFI. In the end he ended up having to reinstall both OSes as everything went pear shaped.

Make sure you have a backup of anything important before starting!

TacticalFish · 25 May 2016 at 15:39

Thanks for the input guys, think I'm just going to have to install over it. Doesn't seem worth the hassle.

SMN · 27 May 2016 at 10:21

If i were you and you want to keep it simple (and you can), add another hard drive, unplug the ubuntu hard disk, install windows 10 on the new disk, plug the ubuntu disk in and then:
A) Easy option, use BIOS to choose your OS.
B) Modify Grub on Ubuntu and then set BIOS to boot to the Ubuntu HDD every time.

Shrinking partitions, etc is a recipe for disaster if you arent confident.

TacticalFish · 28 May 2016 at 16:47

SMN said:
If i were you and you want to keep it simple (and you can), add another hard drive, unplug the ubuntu hard disk, install windows 10 on the new disk, plug the ubuntu disk in and then:
A) Easy option, use BIOS to choose your OS.
B) Modify Grub on Ubuntu and then set BIOS to boot to the Ubuntu HDD every time.

Shrinking partitions, etc is a recipe for disaster if you arent confident.

Thanks for the advice, it's a very good idea. Having been through the files properly, I've realised I've got most of what I want to keep on DropBox. So I've decided to just install Win10 over it all.

First snag, can't boot from the ISO I've put onto the USB. It's a 32gb SanDisk, plenty big enough. Used Bootcamp assistant to make it on my work Mac. It's registering as WININSTALL on the mac, so I guess that the problem lies within the machine I'm trying to boot it from. Specs:

CD: 24X Double Layer Dual Format DVD+/-R/+/-RW + CD-R/RW DRIVE
CPU: AMD Athlon(TM) II X4 640 Quad-Core CPU w/ HyperTransport Technology ***Overclockable XXX***
FAN: AMD ATHLON64 CERTIFIED CPU FAN & HEATSINK
HDD: 500GB SATA-II 3.0Gb/s 16MB Cache HDD (Single Hard Drive)
MEMORY: 4GB (2x2GB) PC10666 DDR3/1333mhz Dual Channel Memory
MOTHERBOARD: ASUS M4A87TD EVO AMD 870 Chipset CrossFireX Support DDR3 Socket AM3 ATX w/ 7.1 Audio, GbLAN, IEEE1394a, USB3.0, SATA-III, RAID, 2 Gen2 PCIe, 1 PCIe X1, & 3 PCI ***Overclockable S&S*** [+33]
POWERSUPPLY: 600 Watts Power Supply
VIDEO: ATI Radeon HD 5450 PCI-E 512MB Video Card

I would try boot from a CD, but the drives broken..

Are my CPU & MOBO just too old to do this?