You should check in your power options and see if it's set to turn the monitor off after a certain amount of time.

Does it show your BIOS screen?

The other possibility is that the resolution is somehow getting set too high for your monitor to handle, resulting in the monitor shutting off.

Oh yes, the problem came back again, even I had adjusted my power settings in Vista. This time, while using the computer, a Blue screen came out of nowhere and the monitor went into hibernation mode (i determine this by the orange LED on the monitor, green means it's working and signal is connected).

Sometimes, when I startup the computer, the screen blanko. And apparently there is nothing I could do, except pushing the reset button (i think this is dangerous!).

Can someone share some insights into this? I thought of formatting my system, in case there are vicious bugs in there. Any ideas?

Thanks.
Ash