Unable to delete a .bak file.

Hi everyone,

I have a .bak file of 200Gb, i copied it to the test server, it took around 6 hours to copy.

Now when I tried to delete it from the main server i got the below error:

"Error deleting file or folder
Cannot delete [name of folder]: It is being used by another person or program. Close any programs that might be using the file and try again."

I restarted the SqlServer services but no gain.I even logged off from server ,but no effect.

Please suggest what is to be done.

Regards,

Hunt