This may help:
To diagnose the problem, create a power report. To do this, follow these steps:
* In the Search programs and files box, Type cmd.
* Right-click CMD, and then click Run as administrator.
* At the command prompt
, type powercfg -Energy -output c:\temp\energy.html, and then press ENTER.
* In the Temp folder, open the Energy-report.html file. This report uses a 60-second run. However, the report time is configurable.