By any chance is your keyboard a Millennium Keyboard? I also lost the green bars, but just figured out how to get them back. I had to update the driver for the keyboard ... even though I had reinstalled the drivers with the disk originally, it needed to be forced. Here are the directions I followed:
1. Turn your system off.
2. Connect your PS/2 Millennium Keyboard to the PS/2 keyboard port of your PC.
3. Turn your system on and start Windows.
4. Open the Control Panel by clicking Settings from Start Menu.
5. Double-click System icon and select Device Manager tab.
6. Expand the devices under Keyboard, locate the device you want to update (
for example, "Standard 101/102-Key or Microsoft Natural PS/2 Keyvoard") and
double-click on it.
7. In Properties page, select the Driver tab and click on the "Update Driver..."
8. Select "Specify the location of the driver (Advanced)" item and click "Next"
9. Choose "Display a list of the known drivers for this device, so you can
select the driver you want" item and click "Next" button.
10. Click "Have Disk..." button. In the "Install From Disk" dialog, input the
right path of driver (for example, "A:\Me") or click "Browse..." button to
look for driver manually then Click "OK" .
11. Choose "PS/2 Millennium Keyboard" and click "Next" button.
12. Follow the on-screen instructions to complete the driver installation.
Good Luck !!! I hope it works for you.