What program will tell me what other programs/services/modules are doing?

Im looking for a program that will show me anything and everything that is happening to my computer, from what DLL is being called on by what program/service, to what program/service is creating what temp/permanent file in what folder. I know this program exists, i have used it before, but for the life of me, i cannot remember what it's called. The only thing i know is it's a freeware utility, like Procesplorer, and is download-able from Microsoft.