LockHunter - It is a free tool to delete files blocked by something you do not know.
WinSpy - Retrieve window information.
FileASSASSIN - FileASSASSIN is an application that can delete any type of locked files that are on your computer.
Winspector Spy - Have you ever used Spy++ that comes with MSVC?
IObit Unlocker - Never Worry about “Cannot Delete Files” on Your PC
Window Detective - Window Detective is a programmer's tool used to "spy" on an application's windows...