When i turn on the computer the LCD show a green light and suddenly they turend in red light and then blank screen showen...what the saolution?

Perform a Flash Light test as shown below LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...

ViewSonic LCD (VA1912w) Went Blank

I am using this great LCD for about an year. But few times in the past my LCD didnt show up the display though the Green light was still ON, turning off the LCD and opening it again always solved the problem. But now My LCD completely went blank. Turning off/on didnt work at all now. I've tried couple of other tweaks mentioned on this site but they didnt work. I am just seeing a blank screen with green light ON. and ya theres a very low hissing sound coming from the LCD.

Since you have tried another monitor with your computer, then we can only assume that your LCD monitor had gone bad.
If the light is green but you can't see anything on the screen, then most likely the backlight has gone bad. Unless you want to take the monitor apart, I would suggest buying a new monitor.

You may have failure in the power supply due to bad caps, bad inverter circuits such as shorted transistors, transformers, bad lamps. You need to open it up and make some measurement, see example of failed ACER monitors: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further.

try to charge phone battery in 12 volts dc

ViewSonic LCD (VA1912w) Went Blank

I am using this great LCD for about an year. But few times in the past my LCD didnt show up the display though the Green light was still ON, turning off the LCD and opening it again always solved the problem. But now My LCD completely went blank. Turning off/on didnt work at all now. I've tried couple of other tweaks mentioned on this site but they didnt work. I am just seeing a blank screen with green light ON. and ya theres a very low hissing sound coming from the LCD.

when i turn the computer on the light on the monitor blinks green but i cant get it to turn on..i have a black screen.

If you power switch does not light up. It possible that the Horizontal Output Transistor (HOT) is shorted.

try to start your pc in safemode with vga mode with thjis faulty monitor
hope you know how to do it
start pc (powerr on)
then continuously press F8 key then it will show you boot menu
select safemode with command prompt
then if it show desktop on screen this means your monitor is having problem with resolution try to downgrade your monitor's resolution
rightclik on desktopgo to properties
select settings
here you can find screen resolution make it to 800X 600 just for one time
then restart your pc it will auto select proper screen resolution

Looks like one of your backlights is bad, first indication is the red or pink tint, replacement of the lamp is fairly easy. If one lamp is bad the inverter will not work. You can get a replacement lamp from Mouser electronics for about $12