I don`t know if this range of boards is meant to do this, but a number of boards do a quick restart from powerup as a self diagnostic thing.
Newer bioses tend to get rid of it.
The long beep and then 2 short reminds me of memory issues. I`d try a single strip of memory in each of the slots to get it to boot with a single beep (which is generally regarded as good), then pop into the bios and be sure that the memory settings are adequate for the memory u have. Voltage usually. Often defaults to 1.8 when 2.1/2.2 is required.
Doesn`t sound like a new build tho as u have windows installed.