So I have now fit the RTX 5070ti and completed a full re-instal of windows and the computer (so far) has not shut down! It's been about 3 days now so hopefully that issue has resolved itself! I have noticed since the re-install though two things, sometimes I get an error and I'm greeted by a blue screen with error code 0xc000000e Error - Your PC/Device needs to repaired hoping maybe sfc in CMD can sort this but will try once I'm home. The other thing which may well be because of that issue but the boot up process is very slow now. It used to turn onto the login screen very quick, now it takes a good 30 seconds or so.