I have solved my problem! Here is the conversation with online intel chat customer service staff:
info: Please wait for a site operator to respond.
info: You are now chatting with 'Adolfo'
Adolfo: Hello. Thank you for visiting Intel Customer Support. How can I help?
you: I bought a new Intel motherboard DG41TY yesterday. I have installed everything, then when I boot up, here is what happen: 1. first I hear a beep 2. intel logo show 3. second beep 4. windows logo and start to load as normal, everything work fine So there isn't any error message, just I have never used any computer that would give me 2 beeps. I know there is beep code that indicate any problem while boot up, but it doesn't look like any problem at all, no error message and everything run fine. Is this just the new style of Intel motherboard? Or my motherboard has some serious problem so I should return to the shop? Thanks a lot!
Adolfo: Allow me a moment please
you: sure thanks
you: and I have updated to the newest bios, it is still the same.
Adolfo: Ok the first beep means that the system is booting up, the 2nd beep means that the system detected devices, so this is a normal behavior on our current motherboards.
you: thanks a lot you are very helpful
Adolfo: Thank you for using chat. I look forward to chatting with you again. We value your suggestions and would appreciate it if you would take a moment to complete our survey. The survey will appear when you click "Close'' to close the chat window. Have a nice day.