PC doesn't boot or beep after sending the components overseas

So, my history is this:

I have a PC with an ASUS Motherboard, a intel E8300, HD6800 and a Corsair 650W (This last two are barely new).

My PC was working perfectly in one country, I unmounted it, I put all the components in their boxes except for the motherboard (bubble wrap, I didn't have a choice)

I sent the components overseas, I received them, I bought a new case and mounted it again.

Now comes the problem, with everything connected except for the hard drive (being 100% sure the power is correctly connected) the computer doesn't boot. The fans are on, the light in the MB is on, but nothing happens, no beep also.

Next step is to try everything with the minimun components, so I put the MB out of the case, and I try without Graphic Card and hard drive (only CPU, only CPU and RAM, even nothing). In any of the cases I heard any beep (the speaker is connected).

My guesses: I don't think is the PSU because is a Corsair brand new, it was working before sending the components and I sent it in its own case well protected.

I really think is the MB, because if the MB was good, at least it will beep! And also, sending the MB in bubble wrap I don't think it was a good idea.

What do you think? How can I be sure where is the problem? I don't have other computer to try components on it.