Older CRT displays. To fix this I installed a power sensing AC power bat like this one -> http://www.treehugger.com/files/2005/12/smart_power_str.php
This is cheaper than replacing the old monitor and "green."
my problem my monitor won't turn off. otherwise it runs great checked with pc and it says monitor is running proper. when pc goes to sleep or turned off monitor stays on. it looks like a big white light. this is my first computer but I am not entirely a newbe i have checked everything i know and all i get is monitor running correct. i would greatly appreciate any help i am 67 and disable and my computer is my best friend thank you