How do I set the BIOS settings to allow the monitor to power off???
There is no way to shut the monitor off through BIOS.
What are your settings at in Power Management?
Control Panel-------->Power Management------->Under the Power Schemes tab (select Home/Office Desk) then below that you will see Settings for Home/Office Desk power scheme the setting for the monitor should work set at 15 minutes.
The above is how my settings are with 98SE. Hope this helps....