Googling your mother board (Asus) and expecting the BIOS to be found is not the correct thing to do. You need to Google the BIOS type (I think yours is AMI) which you can see on the BIOS screen which you have had acess to. So to find out beep codes for that you should Google "AMI beep codes" which would produce several hits including click here
To answer your questions:
1. Each BIOS has its own set of codes. The BIOS is used by the manufacturer of the motherboard therefore you can find the same BIOS on different manufactures boards.
2. Many things can damage A CPU. Most modern CPUs have over temperature protection but a faulty PSU could cause problems.
3. You could have a faulty PSU, short circuit, bad connection, faulty graphics board or any of a number of other problems. I should start by ensuring the mother board achieves BIOS boot in the case with nothing else connected to start with.