u/Comfortable-Double79

For context, I don’t know much about pcs. I bought this one from my coworker 6 years ago and he said he built it 7 years before that for $2500. The only thing I have added is a rtx 2060, and a couple sticks of ram. It’s been working fine up until recently when it’s started shutting off when playing certain games. After some research I assume I’d need to replace the power supply, but since my cpu is so old (intel i7 4770k) I’d want to replace at least that too. My question is: if I’m going to order some parts to replace old ones would it be better to just take the gpu and sticks of ram I bought and build a new pc, or would it be okay for me to just replace some of the components?