I recently upgraded my 1 year old custom PC from some cheap FM2+ dual core CPU to a Ryzen 3 1200. However, after installing the new CPU, mobo and RAM, the PC would start but not boot and the monitor would display the message "no signal". The HDD used to be fairly noisy as it is quite old, but now it only makes some noise when initially starting up and them hums very quietly. I have tried re-installing the RAM (although not changing slots as the cooler is too big) & clearing the CMOS by both connecting the two pins and removing the mobo's battery. I have also tried using both my GPU (RX460) and the onboard graphics (using both HDMI and VGA) and have removed all unnecessary cables so that it is just the front panel connecters, power cables and CPU fan. I have tried using the motherboard both in and out of the case and so I am really at a loss as what I should do so I took to the internet in the hope that someone smarter than me would figure it out.