Why does my computer make three long beeps

G'day all,

I have just bought a brand new motherboard (GA-990FXA-D3 AMD).
I've inserted a new compatible ASUS 560 DCII 1gb.
I've inserted 2X4gb ddr3 Kingston 1333 which also compatible with this motherboard.
I've inserted a AMD Athlon x4 cores 640 which is also compatible with the motherboard.
I've inserted a 2 gb Seagate green sata and card reader with USB2.
I've also inserted the Samsung BlueRay disk combo.
Inserted Windows 7 Ultimate 64bit software and all drivers pack which came from my motherboard.

All this worked when I booted and worked without any errors whatsoever.

A couple days later I pushed the start button and I get three long beeps and nothing showing on the monitor,three long beeps go off in intervals of about 5 seconds.

What I did:
1. I unplugged all peripherals, cables, power cord etc according to Gigabyte manual Handbook except the CPU (only detached power to it.
2. I made sure there can be no short circuit by wearing short circuit wrist and worked on plastic.
3. I started the computer no 3 long beeps present.
4. I turned the computer off and always unplugged the power cord.
5. I plugged the power cord to the CPU and again it made the three long beeps.

(All these peripherals and GPU, HDD, keyboard an mouse, card reader, USB2's, monitor,optical drives, dvd drives and power cord was taken out and turned off and unplugged.
I did not take my CPU out but left the power unplugged).
6. Plugged the power to the ATX 12V motherboard and to the main.
7. Turned the computer on again. Again the three beeps were present.
8. I took out the memory cards and disconnected the CPU power.
9. Turned computer back on again no beeps were present.
10. I plugged CPU back in again, three long beeps were present!!!!!

The motherboard, DDR3 1333 2x4gb, Asus 560 DCII, card reader are brand new.

It seems there maybe something wrong with the CPU. I check Gigabyte and checked whether Memory, CPU, Graphics card, OS and are compatible with this new motherboard. Bear in mind that this computer was working for a little while.

Anybody with this sort of trouble, please don't hesitate to help as no answer is a stupid answer to me.