I suspect all you are missing is a Mint17 graphics driver for your hardware, or a "compatibility mode" argument to the kernel. That is, Mint17 has never been stable on your machine, just stable enough to make you think it's properly installed. If you boot a Live-Session Mint17 in Compatibility Mode, do all the problems go away (ignoring any Software Rendering message)?
Will you post the output of...
Code: Select all
inxi -Fxz