Monitor turns then shuts off...will not stay on

Make sure the power cable is firmly plugged into the monitor and into the wall. If so, you may have either a marginal power-supply to the monitor or the monitor electronics may be failing.

If there is a power-brick (adapter) on the power cord for the monitor, make sure the wires going in-to and out-of that are not loose or damaged. Consider a new power cord before condemning the monitor.

If you turn your monitor on and when its on you go into your computers settings. Where you can fix your monitor and fix the resolution and all that. There should be a thing there where you can put never shut off. You have it on 5 to 10 minutes to shut off. That will keep the monitor from turning off again. I did this with mine it kept shutting off to. Thanks for posting I hope this helps you. I am sorry I couldn't be more detailed. i have been up all night lol.

On your Desktop, Right Click the mouse and Select Properties.
Click Screen Saver tab and Select Power. Change Turn Off Monitor
to Never. Your monitor should stay ON forever, until you turn its
power OFF.

Whenit power up and stays if the display picture is good, the fault can be a dry soldering, poor joint or a thermal runaway of one of the power circuits.
In all the above you can open the monitor , tap and see or look with a magnifier for visible dry joints.
You can also check if any semiconductor or IC is heating up beyond to shut off.

Time for a new monitor.

Ok, another words, monitor powers up for few seconds and shuts down by itself. If green LED on the front panel turns off as well or stays on?
If stays on, then inverter turns into protection mode because of old backlight lamps.
If it turns off in same time with an image on the screen, then there are some bad electrolytic capacitors in the power supply.

Does the power light stay on? If so, you have an inverter problem. If the power light goes off, you have a power supply problem.

I am having the same issue. Stays on for 2 seconds then goes black. If I find a solution I'll let you know.

try using a different monitor, borrow one if you have to, if the monitor works on your computer, then it simply means you need a new monitor. As far as the computer shutting down, it may be recording the bad monitor as an error in the loading process and automatically shutting down.

It sounds like the picture tube in the monitor has burned out. Time to replace.