If you own a laptop with UEFI (normally Windows 8 pre-installed PC), you can natively install Ubuntu and Dual Boot ith your current Windows 8/8.1 by using the steps below.
This tutorial is base on what I did with my Acer Aspire E 15 series.
1. Create a new disk space for ubuntu installation.
You can do this by open Disk management and shrink volume to create a new unpartitioned space (Free Space). I recommend 30GB.
2. Turn off Fast Startup
Go to control panel - hardware and sound - power options, the select change what power button does on the left panel. Turn off the fast startup bu uncheck the box.
3. Restart with advance setting. Press restart and hold the shift button on your keyboard. Select troublshoot and advance option. Now select UEFI Firmware setting.
4. Change UEFI Setting
To enter UEFI setting, press F2 upon boot - for model other than Acer the key might be DEL, ESC or F12.
Now make the following changes.
A -- (Only for acer) set a password for your BIOS so the option to disable secure boot is available.
B) -- Disable secure boot.
C) -- Change UEFI to Legacy
Press F10 to save change and restart. Insert your bootable Ubuntu CD or USB.
6. Now boot Ubuntu with your bootable Ubuntu CD or USB. Select install Ubuntu.
7. Now for the last part. on the installation type select something else, look for the new disk space we created earlier. Create 4 new partitions for ubuntu installation:
Assuming you have 30Gb of disk space:
root = 10GB
boot = 1GB or less
swap = 4GB
Home = the rest of disk space
Now continue with ubuntu installation and reboot. The problem now is if you want to boot to windows 8 you need to press F12 and select windows boot manager. If you want to boot to ubuntu just boot normally.
If you change form Legacy to UEFI on your UEFI setting, you will not be able too bot into ubuntu. So just stick with legacy mode.