external hard drive corrupted :(

Hi guys, last week i leant my 1tb iomega external hard drive to my friend. He called me 2 days later said that it was inaccesable. He told me that he didnt just plugged it out of the pc and that he safely removed it but i think he just either switched off the plug or pulled the usb out. Now i tried to

• format it but it tells me "the disk in drive e cannot be formatted".
• I tried with cmd " eirror in LOCTL Call.
• Checkdisk when it starts it closes
• tried defragment : defragment is unavailable "processing aborted due to : the parameter is incorrent"

Can someone give me a suggestion