The crash is not common to all machines - there is support option at http://research.microsoft.com/en-us/projects/joulemeter/download.aspx but again, this is a research preview and may not work for everyone.
The taskbar launches and immediately MINIMIZES ITSELF TO THE SYSTEM TRAY. This is to allow convenient access to it from the system tray whenever you wish to look at it.
The tool is expected to be useful for: users interested in seeing the energy consumption of their PC and IT pros interested in estimating how much the energy usage in their IT setup is (and how it has changed with new power management settings and group policies).
In the longer term, this might also be useful for software developers to decide among multiple software design choices to pick the energy efficient choice. The developer may have a trade-off between using x% more CPU or y% more disk (using compressed IO for instance). The power model learned by Joulemeter gives a common currency to make such trades.
GPU is not straightforward to model here since much of the activity is managed in hardware and the OS only gets a limited view into how heavily used the GPU is. That said, there are some hints the OS has about what the GPU is expected to be doing and that could be explored for doing a GPU power model...