Hlp: Monitor HW problem trouble shooting

Hi everyone:
I live in CA...yes , we have power problem. My monitor
stop display anything after the first level 3 alart of power shortage. After I unplug it for few minutes(vga cable + power), it get back as there was no problem. The next morning, it stop display again. This time, it take 2 week.
then it went back and went out. now it take another day.

I am not sure it's the unstable power or the natural death of this 5 yr old nec xp17. It seems fine and works as
I am composing this msg, the problem it I don't know how to prevent the black screen issue. by the way, every time I turn on the monitor despite black or working, I can hear the zzz(anti static?) sound all the time.
If you know the steps to find the actual problem, pls let me know. Will a power regulator do it?

john