Hello, and Welcome
Something like this is hard to track down. I would first powercycle the computer. Unplug the powercord, hold down the power button for 30 seconds. Replace the power cord and boot.
If this does not work open the computer side panel after removing the power cord. Touch some bare metal of the case. Look for the CMOS battery and replace with a new one. After replacing the battery, powercycle the computer again and see if it boots up. If it does, go to BIOS settings and set it back to default and then save.
Edit: This could be a bad Power Supply. If you have a multimeter, you can test the PSU but only do this if you are comfortable working inside the computer.
Edited by JohnC_21, 28 September 2014 - 04:42 PM.