I have a variety of desktop PCs with ATX power supplies, these PCs run Windows XP or Windows 7; I need to know their current power consumption in Watts.
This project is to provide a programming solution for this technical problem, it is preferred that you implement an application using said solution but this is not required, only the solution is required.
Your solution cannot require additional hardware such as an external power meter.
Ideally you will provide a method to directly query some generic function(s) that are available on XP and Windows 7 such that you can calculate the current power usage in watts.
You can list the desktop PCs' components separately and query them individually calculating a total consumption, or provide a method to just see the total current consumption in watts.
You should specify in your bid if you are providing the solution or if you are providing the solution with an application that it can be immediately tested.
As per basic requirements the application or solution needs to function correctly to be acceptable, it will be tested on a wide range of dissimilar machines and must function on all.
If you can not provide a full solution but can provide a partial solution (such as one that is manufacturer specific) I may be willing to accept this provided it is discussed prior to the project starting.