Windows Task Manager tells you what applications and processes are running, but some process names aren't very clear to the casual reader. Process Explorer helps you get to the bottom of things by digging down to see which application started a process and which resources that app is currently using. This excavation can be a big help when you're trying to figure out which background processes you dare shut down. It can even help sniff out spyware, too.

very network admin should know about Sysinternals.