If Changing the BIOS settings didn't work, try using RUFUS it works much better with linux when creating a bootable usb, And if that still does not help, try the F buttons (F9/ F12 for Acer: F12 for Dell)) and i HIGHLY recommend using different partitions for your linux and windows rather than installing along side of (i have 50 GB each for both my Linux and windows uses the rest) If prompted to install boot-loader.. YES definitely. Luckily Ubuntu is Debian based (one of the easiest to figure out so it will use the simple GRUB boot-loader.
I currently have 3 Os's on my laptop, 2 linux 1 NT based and i have had ZERO issues with switching between them. if you have anymore questions feel free to ask.
EDIT: It's Best to do a SHRINK VOLUME inside of windows then format the new partition you just made (fat32) then stick the usb and try from step one, the linux should see that space you created as unused and be able to install to it no problem( you MAY need 1-3 GB SWAP space)
Edited by Viper_Security, 21 June 2016 - 03:38 PM.