Sorry to state the obvious but I work in a technical field and I often overlook a simple solution after hours of work. Be sure to check the power cord. Not just at the wall, but into the power supply. Also check any breakers on any power strips to make sure one didn't trip. Or perhaps the pwoer switch on the power supply itself got turned off. It's unusual for a power supply to go bad while it's off! If all else fails, you can pick up a new power supply fairly cheap at any computer store. Good luck!
-- Ah sh*t! sys64738 --