I have an old HP Pavilion 700 that I am having trouble with. A few months ago, I replaced its power supply because the fan inside of it would start up for about a second and then shut off. The problem I am having now is the fan (shown in pic) connected to the motherboard is shutting off at random times and causes the external display to go blank. But the fan inside the power supply will always stay on though. Sometimes, I can get the computer completely booted up for about 10 minutes and use it just like normal before this happens. Other times, I can only get as far as the startup screen before the fan and screen shut off. Any ideas of what the problem could be?