This PC has just been built. I plugged my HDMI cable into the GPU for the first time, and the speaker beeped once and the monitor started flashing green pulses. This stopped when I put in a flashdrive containing my graphics card driver, BIOS, and utility (as well as my mobo BIOS and drivers). I was able to start installing Windows 10, but it crashed halfway through installation and started flashing green again. Furthermore, the power button on my chassis turns my PC on, but can't turn it off. I've been having to flip the switch on my power supply to turn off the system. I'm using a GEFORCE RTX 2060 and a Polaroid 22" TV. I'm connecting the two via HDMI cable. I need HELP.