Unlocker - unlock a file from a lock

The following messages are thrown by the OS when we delete a file:

Cannot delete file: Access is denied. There has been a sharing violation.
The source or destination file may be in use or the file is in use by another program or user.
Make sure the disk is not full or write-protected and that the file is not currently in use.

Use Unlocker - the explorer extension- that allows you to unlock and then do these operations.

You can download Unlocker from http://filehippo.com/download_unlocker/