I have a Dell XPS 420 desktop computer. I have owned it for over 10 years. it has worked well. When I tried to power it on, it would not power on at all. I removed the computer cover and I noticed there was a lot of dust inside the computer. I think the cause of the computer not turning on might be the power supply. Does anyone have any suggestions on how I can fix this issue and what might be causing this power issue?