Monitor not coming back on after inactivity

We have a Gateway EV730 17" monitor, about 5 years old. Recently, it has started to give us trouble after a period of inactivity (usually overnight). The monitor is set to have the screen saver come on after about 10-15 minutes, then it's set to "turn off" (the green light is still on though) after about 30 minutes. Normally, when coming back to the computer, you move the mouse or press a key, and the monitor comes back on. If the tower's light is green (standby mode?), the desktop comes on. If the tower's light is orange (hibernate mode?), the monitor will show the screen where you have to click on the admin's name. Lately, the monitor has not been coming back up with the move of the mouse. Sometimes, if you press the power button (off, then on), the monitor will then come on. But, sometimes, it will take several tries of this before it will come back on. Today, it took about ten tries (and 10 minutes!) before it worked. What can I do to fix this? All cords seems to be ok. Are there any settings I should check or change? Or is this monitor about shot?

 

Anyone?

I changed the setting to where the screen savor shuts off after 5 hours, so that keeps the monitor on, but I was wondering if that was ok for the monitor?

 

I never use a screensaver. If I'm going to be away from my computer and still want it on, I turn the monitor off with the on/off switch then turn it back on when I return.