i have an acer eg43m mobo with this gateway dx4822 desktop w a 300w ps.
"monitor keeps shutting down" What do you mean when you say that ?
No video doesn't necessarily indicate there is anything wrong with your monitor or your video adapter - other things can be wrong.
Have you tried your monitor with a different computer ?
Have you tried a different monitor ?
When does it stop showing video ?
If it always shows video fine while booting but then there's no video after Windows starts to load, that's usually easy to fix.
If the computer displays video fine for awhile after it has been booted after the computer has had a chance to cool to room temp, then the mboard shuts off and stays off, that's probably an cpu overheating problem.
Are you using a video card installed in a mboard slot ?
If yes, what is it's model ?