This can be very helpfull for "hanging" application problem diagnostic. The information provided is mostly technical, but may provide us with answers for the further proprem diagnostic.
I quote:
For more info check the url above...Sometimes, a Windows software hangs, the user interface doesn't respond anymore, and you cannot find out what is cause of the problem. This utility tries to detect the software that is currently hang, and displays some information that may allow you to understand what exactly cause the software to hang.
Most of the information displayed in the report of WhatIsHang, like Call Stack, Stack Data, Processor Registers, and Memory Data, is designed for users with Windows programming knowledge. However, WhatIsHang also displays a list of strings and dll files related to the hang problem, which can also help users without programming knowledge to understand the cause of the problem.