I went to restart my desktop computer (everything was working just fine before), I think I may have hit the lock button. (Vista Premium operating system). The minitor went balck and only displayed "no signal". The green light went to amber. I then turned everything off. Started monitor, then turned on computer. The computer acted like normal to reboot. The monitor indicator light came on green (no screen display) then displayed "no signal" and the indicator light went to amber. Computer stayed on throughout, but no display on monitor. I think the monitor is sleeping. How do I get it to come back on?
Issues like this are almost always with the computer, not the monitor. If you get a no signal message it means the monitor is on but no signal is coming to it. Check the video cable. If that does not work, try another monitor. People see the monitor say "going to sleep mode" and think it's the monitor issue that it's doing that, the real issue is that the monitor is not getting any video signal so is going to sleep mode.