PSU has multiple outputs. There is 12 volt rail, 5 volt, 3.5 volt, etc, etc. Any of them can fail, and cause big prblems. They make very inexpensive PSU testers that can be purchased almost anywhere for around $20.00. Or, if your good witha multi meter, you can check that way as well. That is only way I know for sure to check a psu. But, if I were forced to guess.....I'd agree with geekapproved that it sure does sound like your psu failed. good luck.