So recently I bought a used Inspiron 570 and I got a new power supply, graphics card, and a new CPU for it. When it came to upgrading my pc I ran into an issue. I placed the refurbished CPU (AMD Athlon x4 640) into the motherboard along with my new power supply and graphics card. The computer turned on but nothing displayed on my screen. It wasn't a graphics card issue because I also plugged the monitor into my motherboard and nothing was displaying it either. I took out the x4 640 and put the Athlon 250 back in and it turned on and the screen received a signal. I tried reseating the CPU to see if I sat it wrong but still, nothing came on the screen. The motherboard is a dell 04gjj motherboard. I was told that I should update the bios and I have checked and the bios is a few months later than the most recent bios upgrade. I haven't done the bios update yet and I was wondering if there is something else that I might need to do or if I have to update the bios. I am aware that the CPU might be defective.