I had the same problem on my Asus machine. Try this, Highlight the try Ubuntu in the grub menu and then press the button e then in the line with Linux add the below command just before - - -
and then press F10 after it. It disables the graphic driver and will now boot and won't freeze. Just make sure while installing to get the appropriate drivers during installation itself. I didn't do it so it got stuck for me on the purple screen after reboot.
If it also happens with you after rebooting. Then you should boot in the recovery mode and then install the graphics and missing drivers from the additional drivers in the dash. After that you will be able to boot up your Ubuntu.