I built my computer about six months ago and suddenly today when I tried to turn it on, it would cycle on and off. It was working just fine this morning. My computer if perfectly clean since I had used compressed air to clean it a month before and it had been working perfectly fine until now. I have looked at my POST LED indicator on my mobo and it has no error messages. It only goes up to early memory initialization and then repeats the cycle. I noticed that the PSU makes a switch sound when it turns on and off, is this normal too?