one of the usb devices has malfunctioned

I was copying a rom onto an sd card and went to check something else whilst it was copying when i looked back for some reason everything on the sd card had been erased and now i keep getting "on of the usb devices has malfunctioned" when i try to put the usb sd card reader back into my laptopany help would be appreciated thanks

Try another reader.

try a different (not on the same stack) usb port, the malfunction warning usually means the device isnt getting enough power from the port its in.