By default, windows xp's welcome screen (the screen which displays either the logon box or the fast user switching screen) is run with power management entirely disabled. Laptops will happily run in full power mode, even if they are running on batteries. Quite a sucky state of affairs.

Like in windows 9x, the welcome screen uses the registry of the default user, but unlike 9x, there's no way to logon as default (pressing ESC doesn't work anymore :) So, to set power management settings for the logon screen:
  1. Log on as administrator1, and set up power management as you see fit
    (I recommend setting 'turn off monitor' to 1 minute, and 'turn off hard disk(s)' to 3 minutes if your system can handle it.2)
  2. Each user's power management settings live in (HKEY_CURRENT_USER\Control Panel\PowerCfg). Open regedit to here, and export the whole key to a file.
  3. Open the file in notepad, and replace every instance of 'HKEY_CURRENT_USER\' with 'HKEY_USERS\.DEFAULT\'
  4. Delete the key 'HKEY_USERS\.DEFAULT\Control Panel\PowerCfg', and import the .reg file.
  5. Reboot.
The power management setting for default user only apply when no users are logged on. When one or more user is logged on, the welcome screen inheirits the configuration of the last logged-on user.

1 - only administrator has write access to the default user registry hive.
2 - Some can't - every time a hard disk spins back up, it generates an ATAPI error 9 (timeout), and after enough of these windows disables bus mastering for that drive. Ouch.

Log in or registerto write something here or to contact authors.