Hi and welcome.
The first thing to do is remove anything that might be causing the problem. So take out the sound card, the wireless card, optical drive and any other items that you have connected that are not essential.
Next put in one stick of memory into the first slot and leave the other slots clear.
Remove all the power supply connections and then replace the 24 pin and the 8 pin ATX near the CPU.
Make sure that you have the motherboard speaker(buzzer) connected the right way around.
This should leave you with a very basic system.
Boot up and note any beep code that is produced. Now post back.