Earlier, I posted suggesting you back up your computer. I did this because mine did not want to start up normally. After I backed it up, I shut it down and opened the mid sized tower case. I found that the case vents were partially plugged with dust. The inside of the case was pretty clear . I blew it out carefully with canned air. You do not want to damage the case, video card or cpu fans. It is a good idea to routinely check the case ventilation.