Cannot Delete xxx: Access is denied Make sure the disk is not full or write-protected and that the file is not currently in use

Have you come across the annoying error when try to delete files from you computer or even external harddisk? 

I've tried to change the permission setting in security tab but i cannot do anything because only system can change the setting. 

Finally, i found a tool named unlocker http://download.cnet.com/Unlocker/3000-2248_4-10493998.html that help me to delete the files.

Hope this help.