How to know wich program is using a file?

[Bazikstano]

It is tipycal that when you want to delete or rename a file it comes and error telling you that it is in use. How can I know what or who is using the file?

Greetings from Chile
Bz.

[eXceededgoku]

If you use this program called "unlocker" (http://ccollomb.free.fr/unlocker/) you can do this. Woulda though Microsoft would have been smart enough to add this feature in Vista.