Our computer has had a problem which started with the screen turning into power save mode. Computer has been away and we are told it works perfectly now but when we plug in the screen starts up with LG but...
Have you tried another monitor on the computer to see if the computer is working? When you turn the computer on, do you hear the sounds of normal startup (usually a beep from the computer, then hard drive activity with blinking lights on the front panel, and finally the Windows startup sound through your speakers)? If you do, the monitor may have internal problems, there might be a broken wire in the cable from the monitor to the computer, or a bent pin in the plug at the end of the cable. If the monitor turns out to be the problem, just replace it. It's tough to find anyone to do monitor repairs, and the low cost of LCD monitors today makes it uneconomical to repair them anyway.
But if your computer is still having problems starting up, the monitor will come on, show you that LG logo and then blank out. It's not actually turning off. This isn't happening before anything starts; it's because nothing is starting. The computer's not booting up and there's nothing for the monitor to display. If the computer still at fault, contact whoever it went to for repair. Find out what they did and let them know it's still not right.
ope this helps you straighten things out. Thanks for using Fixya!