one option that you have is to remove and reinstall the ACPI components in Device manager. the issue that you have is power options related. There is a possibility that you will end up removing other components with it, so it is recommended that if you try this, have your drivers CD or exe's ready to install software. If you have a retail PC, chances are it will install all by itself since you don't have a true Windows disc. If you home built it, or had someone build it, grab your motherboard CD. That should have what you need.
Go to Device Manager:
Start>control panel>System
or
Right Click My Computer on the desktop, or if you have it, in the Start Menu. click Properties
Click the Hardware Tab at the top then Device Manager button.
Look for System Devices, click the [+]
look for anything listing ACPI. Most likely will be ACPI power button, things like that. should be in the neighborhood of 3 to 5 items
right click and choose uninstall.
once the unistall has finished, click the computer icon in the menu bar at the top. if you hold the mouse over it, a box should show indicating it is Scan Computer for Hardware Changes.
the hardware wizard will show up. At this point, if it installs automatically, cool. relax and wait for restart.
If not. you have two options. Run the exe for your drivers or explore the CD and locate the proper files. Probably will find a folder called drivers, one for english and one for the model of the hardware.
If you have to install from CD. Follow the prompts to install the software manually. Choose the option to install from disc. choose Have Disk, then browse the disc to the location. Click the associated Next's and should install without issue.
You may have to install using the Windows CD. Be sure to have that handy too.
Again, this is not recommended if you are uncomfortable with these types of component installs. It should remove and reinstall all of the associated files with power management. At which point, you should have your screen options back.
good luck.
-surfer