after a long period of struggle with this strange problem i finally found the clue, sometimes, my LCD goes black itself, the problem is related to the LCD itself, because system isn't been affected and it run normal.
LCD can recognise the input signal, because the signal light keep in blue color (if there is no signal been recognised, it should become orange), but in normal situation, if it goes black, it should prompt a text called "no signal detected", but when this problem occur, it won't prompt that.
my solution is to disconnect its power cord, wait a moment and connect it back again, then the LCD become normal again.
how can i completely solve this kind of issue instead of manually connect/disconnect its power cord every time it occur?
I'm not entirely convinced that it's the monitor's fault.
If your computer has another video card connection (a motherboard integrated, besides a dedicated standalone video card), does it show the same symptoms with that?
Don't you have another computer, maybe a laptop, to test the monitor?
Could be cable fault, too...
Anyways, if you get an electricity splitter with a switch on it...
in fact, my video card is the integrated one, i don't have a extra one.
first time when this issue occured, i took my LCD to a PC store and ask for a test, they used all my components (LCD & power cord & signal cable) to do that test, and nothing strange. then i brought it home and it's all worked well.
i think it is not a good idea to do a replacement for searching the culprit, because this problem comes randomly. the culprit won't appear immediately when i do a replacement.
I had an Asus monitor a couple of years ago that had those same symptoms, it would go black at random times. At first it would happen every couple of weeks, but it got worse over time until it was happening every few hours.
I sent it back to Asus, and they had to replace all the inner electronics of the monitor (and maybe the panel itself, i'm not sure). After that it worked properly, no more black screens.
I'd try using the monitor on another computer for a while to see if the problem persists, that would confirm it is the monitor. if you don't have access to another computer, you could maybe try swapping monitors with a friend or family member for a while and see if they get the same issue.