I have an HP Pavilion Desktop 570-p094. It is about 2-3 years old. This problem happened before and was somehow fixed by cleaning out the fans with Q-Tips, but now doesn't function anymore. My keyboard always lights up first but the mouse, headphones and monitor don't respond. If I switch up the USB port for the mouse it still doesn't light up, even though it works fine on other computers. Switching monitors/HDMI cables don't work either. The biggest problem is that the display no longer turns on. The monitor detects that there is a connection but it returns to sleep mode upon booting the computer. I'm lost and not sure what to do.