Problem with Arduino Leonardo

Hello community!
Some days ago I bought an Arduino Leonardo with Headers, I opened and connected in my computer for installing drivers, but when I connected the Arduino Leonardo with my computer it detects and a few seconds after is disconnected (it doesn't admit Arduino Leonardo), even Windows 7 generates the sound "hardware detected" and then the sound "hardware disconnected".

I tried to install the drivers, but still can not connect Arduino Leonardo with my computer, I have also tried with another miniUSB wire and nothing, it's same. The worst thing is that I have a project with it.

What happened, is my Arduino or my computer (port USB)?

Can you help me, please?

Thanks in advance.

The Leonardo behaves a bit differently than other boards. Trips me up every time I use mine.
Unless something on the board has been damaged, this should help:

I'd also recommend going through the entire page on the link above.