lockhunter.com
LockHunter is a free 32- and 64-bit Windows tool for deleting files blocked by unknown processes. It shows locking processes with detailed information and allows unlocking, deleting, copying or renaming locked files, killing locking processes, unloading DLLs, and deleting files at the next OS restart. Deleted files go to the recycle bin so they can be restored. It integrates with the Explorer menu.