CPU - Either the CPU is not seated properly or the CPU is damaged. May also be due to excess heat. Check the CPU fan or BIOS settings for proper fan speed. Alternatively, try the steps below to resolve your issue:

(1) If any new hardware has been recently added to the computer, remove that hardware to make sure it is not the causing the issue. If after removing the new hardware and your computer works, it's likely that the computer is either not compatible with the new hardware device or a system setting needs to be changed to work with the new hardware.

(2) Remove any disks, CD's, DVD's that are in the computer and if any USB devices are connected disconnect all of them. Reboot the computer and see if anything changes.

(3) Make sure all fans are running in the computer. If a fan has failed (especially the heat sink fan for the CPU) your computer could be overheating and/or detecting the fan failure causing the computer not to boot.

(4) If the above recommendations still have not resolved the irregular POST, attempt to disconnect the Riser board (if applicable) and/or each of the expansion cards. If this resolves the issue or allows the computer to POST, connect one card at a time until you determine what card is causing the issue.

(5) Disconnect the IDE, SATA, SCSI, or other data cables of the CD-ROM, hard drive, and floppy drive from the Motherboard. If this resolves your irregular POST or you now get an error message attempt to re-connect each device one at a time to determine which device and/or cable is causing the issue. In some situations it can simply be a loose cable connection.

(6) In some situations a computer may have power related issues often caused by either the power supply and/or the Motherboard. To help determine if this is the cause of your issue try turning the computer on, off, and back on as fast as possible, making sure the computer power light goes on and off each time. In some situations you may be able to temporarily get the computer to boot.

(7) For users who are more comfortable working with the inside of their computer or who have built their computer, one last recommendation before assuming hardware is faulty, is to reseat the CPU by removing it and putting it back into the computer.

If after doing all of the above, you continue to have the same issue, unfortunately it is likely that you have a faulty Motherboard, PSU, CPU, and/or RAM. The next step would be either to replace these components and/or have the computer serviced. If you plan on doing the repairs yourself or you are a repair shop it is suggested that you replace the Motherboard first, RAM, CPU, and then power supply in that order and/or try swappable parts from other computers.

This might help http://brebru.com/beepcodes.html
BTW: Did you tried unplugging and puggling back the psu?
And what about resetting the bios?