What Process is a small Windows application that lists all the processes running on your computer. When you click on each process, it tells you where that file resides on your PC and it creates a Link to this website which will tell you more about the process. You don't need to download the application though. You can access Task Manager on your PC by pressing CTRL+ALT+DEL and viewing your running processes. Then just enter the process name on this website in the "jump to" Box on the right hand side.
The What Process application is particularly handy in a networked environment as it lets you Connect to PCs across a network, and terminate processes as well as look up what they might be.