Paul Thurrot reported on an issue with Windows 7 machines draining the laptop battery. The issue is with machines that were upgraded.
As Microsoft recommends, and as I wrote in Mastering Windows Server 2008 R2, you should avoid upgrades where possible. You just end up inheriting bad stuff that can make unpredictable things happen.
The tools are there to make it pretty easy to do a clean install. Do a complete PC backup. Export the user state using the tools in Accessories. Do a clean install of Windows 7 (wipe the hard disk). Install any applications and restore the user state. If anything is missing, go ahead and access that complete PC backup that you should have done. XP users can use the tools I recently mentioned to restore to Windows 7.