I've got a dying internal Windows 8 hard drive in a desktop PC. I want to copy the data off of it, but it doesn't boot properly, so I was wondering if I could instead boot from a bootable disk containing a cloning software, then clone it to an external hard drive (connected via USB 3). Then, if and when that is successful, I'd like to buy a new internal HD, pop that in, and then copy the data back from the external drive to the internal one.
What software would allow me to create this bootable disk to perform this backup operation?