boot - usb stopped working after making it a bootable device

My usb is not being detected after making it a ubuntu bootable device..
the second time when I tried to install it on my hard, disk my hard disk stopped working. The hard disks light turns up but its not being recognised by my current windows PC. I don't know whether the problem is with ubuntu or my hard disk. but it damaged two of my storage devices. Now neither of the usb stick nor the hard disk are recognised by my PC.