Hi there! It seems like you're having some trouble with your PC after installing a second-hand RX 470 graphics card. Let's try to troubleshoot the issue.
First, it's important to make sure that all the connections are secure. Double-check the power connections to the graphics card and ensure that the GPU is properly seated in the PCIe slot. Also, check if the GPU fans are spinning when the PC is turned on.
If everything looks good hardware-wise, it's worth checking the temperatures of your components. Overheating can cause sudden shutdowns. You can use software like HWMonitor or MSI Afterburner to monitor the temperatures of your CPU and GPU. If either component is running too hot, it may be necessary to clean the cooling system or reapply thermal paste.
Next, try updating the drivers for your graphics card. Outdated or incompatible drivers can cause instability. Visit the manufacturer's website and download the latest drivers for your RX 470. Uninstall the existing drivers using Display Driver Uninstaller (DDU) to ensure a clean installation, then install the new drivers.
If the issue persists, it's possible that your power supply isn't providing enough power to the system, especially if the GPU requires an 8-pin power connection and you're using an adapter. Consider upgrading to a higher wattage power supply to give your system ample power.
Lastly, if none of the above steps resolve the issue, it's possible that the graphics card itself is faulty. Since it's a second-hand GPU, there's always a risk of getting a defective unit. If you have access to another PC, try installing the RX 470 in that system to see if the problem persists. If it does, then it's likely an issue with the GPU itself, and you may need to consider getting a refund or replacement.
I hope these suggestions help you resolve the issue with your PC. Good luck, and if you have any more questions, feel free to ask!
PH