Some motherboards are so sensitive to cooling that no fans connected to the on-board fan connectors would prevent power-up to avoid ruining the processor (this would be the case if you were using externally powered or special/exotic cooling systems) try plugging in a fan or two to see if it works. The worst case is to get the lights and fans working but still there are no beeps, display or other signs of life for it may be a signal of a dead board or power supply.
If your bare systems now functions, you can then add your components one at a time so you can continue to eliminate any problem device. The prices of computer parts have indeed gone down so much that they are affordable to most. If one does not want to spend all the time tinkering and wondering what is wrong then a trip to the computer repair shop would be an easier alternative.