Unlocker helps delete locked files with error messages including "cannot delete file," and "access is denied." Video tutorial available. MajorGeeks recommends Unlocker Portable which does not include the Ad-Supported Delta Toolbar.
Some errors you might get that Unlocker can help with include:
Cannot delete file: Access is denied.
There has been a sharing violation.
The source or destination file may be in use.
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.
Limitations:
Offers to install the Delta toolbar during installation. Uncheck that by selecting Advanced install. See the video above at 30 seconds for more. Unlocker Portable does not include the Ad-Supported Delta Toolbar.