Loss of Standy By/Hibernate Function

[Mac]

My Windows XP Pro system no longer gives me the option of
going to Stand-By instead of Shutdown. Efforts to change
settings using the power control options in Control
Panel/System yield the following: Power Policy Manager
unable to set policy. Indicates two revision levels are
incompatable."
This problem persist whether on not power management is
enabled in BIOS.
Any suggestions?

 

[CS]

My Windows XP Pro system no longer gives me the option of
going to Stand-By instead of Shutdown. Efforts to change
settings using the power control options in Control
Panel/System yield the following: Power Policy Manager
unable to set policy. Indicates two revision levels are
incompatable."
This problem persist whether on not power management is
enabled in BIOS.
Any suggestions?

What new devices and/or drivers have you installed lately? Something
you installed is not ACPI compatible with XP and that's why it will no
longer enter Standby. Back track and see if you can either remove the
device or driver. It's also possible you may be able to update to a
driver which is compatible.