Low-Power on Olimex-nano

[testadaz]

Hello there,
My project was almost done, almost all the things that I wanted setup when I decided to use a low power lib.
This one : https://github.com/rocketscream/Low-Power
And I added the following line to my code : LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);

I don't know what happended exactly but since then my computer doesn't want commnicate with the olimex-nano.
Every time I got the "unrecognized device" message.

Do you have any solution ? Or does it mean that my nano board is dead ??
Regards