Even my system is showing the same effect. monitor is showing green light but blank screen. what i do is i turn on the CPU no matter it shows the blank screen and then after CPU is on, i unplug the power plug of monitor and plug it again(repeat each time i get a blank screen with green light).I get my original screen back. It worked for me quite a lot of times. even relying on it now also. Its a problem with the monitor not with the CPU or any bios or other. Problem persists till we buy a new one.