can not delete autorun.inf?

Hello
My useb and C and D disk are infacted with utorun.inf virus. I have fomated my usb key 4 time but still can not delete this virus. I used notepad and tried to savea blank file as autorun.inf but I get this error “autorun.inf this file exists with Read only attributes please use a different file name. I also tried to delete it trough command mode but I cant see it in any directory. I scanned with different antivirus but still it is there it not going anywhere.

Regards