It is a new HDD, just once used. And it was working fine. I stored some files.
In the meantime someone else used the drive to access the stored files.
Now I wanted to work again with the HDD, plugged it into the USB - and my antivirus (avast) immediately showed up, telling me that there was 2 infected files found and moved to the chest: Autorun.inf and /ms-dos/ntdlr.com
I unplugged the HDD (safely removed), plugged it later again to see what I can do now - but now the HDD is no longer recognized by my laptop. It does not show up anymore after USBplugged. What can I do now???