DX38BT strange boot, no beep

So i have this kind of problem, maybe not even a problem, but it gives me some concern. Got my hands on totally new DX38BT motherboard, never used, with all the stickers, seals and etc. not touched (found one in storage room when helped for a friend to move his computer shop to other place), assembled pc. And wuola it boots. BUT it boots quite strange. After i press power button pc starts, all fans, hdd's, BD roms start and then after 3-5 seconds shuts down. Then after 2 seconds it starts again and after 1 second it shuts down and then even 1 second does not pass it starts again, boots and i can use my pc fully, no errors, nothing, everything works fine. One more strange thing is that motherboard does not beep after POST. It has integrated speaker but no beep ever. And i cant connect any external speaker for beep codes. There is no connection for it. Well i dont see it. So whats the problem?