I have installed two versions of Ubuntu on two hard drives in my Asus laptop, one running with Ubuntu 14.04 and the other with 15.10. Originally, both systems worked, however, today when booting up and selecting 14.04, it returned an "cannot enumerate usb devices" error, and then froze. 15.10 is starting fine however, this is from where I am writing now.
I made two bootable USB sticks (I tried it from both a Windows machine with Rufus and from Ubuntu 15.10 with unetbootin and the built-in startup disk creator), one with Ubuntu 16.04 and the other with the 64-bit version of Windows 10. All "versions" of the usb sticks return the same results:
Booting from the Windows stick freezes a second after the splash screen with the blue logo appears. Also leaving it for quite a long time (an hour), nothing happens.
Booting from the Ubuntu 16.04 stick shows the initial menu with "Try Ubuntu" and "Install Ubuntu", but it gets stuck at a black screen after selecting either.
The Windows stick is formatted in FAT32 with a GPT partition table, and I made sure it has the file needed for booting.
I have obviously tried changing the boot order, enabled and disabled UEFI boot option, along with several other things.
What could be the reason for this? My aim is the install a clean dual-boot system with Windows on one hard drive and Ubuntu 16.04 on the second.