hello, I have bought a pc from a friend's shop. the components are refurbished except the gpu that's a new Radeon rx570. The problem occurs at random when I am on the pc since the day I bought it. while I'm watching a video or playing a game or even right after logins in on windows, it crashes and the screen is flashing 1 colour while the last sound that played before crash keeps playing on repeat really fast high pitched. I have seen a white screen, Grey, pink red, purple, brown, blue, almost everything. I can't do anything at that point and I just close the pc from the power button. it happens 2 to 3 times a day. Also some days when I power on the computer, fans tunr on light turn on but the display says there is no signal from the pc, when it happens, my keyboard also doesn't light up but my mouse does, even if I change their USB port positions. When it happens, it usually takes a lot of tries of reopennign and closing the computer to finnsly work normally. I have replaced rams(4x2Gb sticks both times) but I still get the same problem.