There's your problem!!
Your Video Card is not powerful enough for the current versions of Photoshop. That video card is fine for "General Computing," like wasting time on Facebook, watching YouTube Videos, answering e-mails, paying bills, etc. Everything else BUT Photoshop. ACR now uses the Video Graphics Processor (Video GPU) in order to function these days. Currently it's still using the CPU / Low-end GPU to work, but Adobe is warning you as time goes on, this will be an issue and eventually ACR won't load at all.
Time for a new Mac!! No software fix for this one.
Well...you could downgrade to an older version of Photoshop CC that last worked with your computer and STAY THERE. No upgrading for you.
Those are your two choices, but you really need a new computer. Start saving. This is such a common problem now, that I've written a very long article about this topic:
Today's Modern Photoshop