I'm having a monitor blinking issue but it seems a little different thn the others. Mine blinks after being off for awhile or being asleep for awhile. It acts as if it is "warming up" and blinking during that time. You can see during the blink that the cpu is completely loaded and ready to go. In fact, you can actually operate the computer if you can get the mouse in the right place. I have loaded and opened my e-mail during the flicker. It began with only taking a few minutes to almost 15 minutes now. I have a GeForce 8600 which had recently had the driver upgraded several times but I honestly can't remember if it started right after or before.
Try the monitor with another computer. If the issue is there also, and you don't want to live with the blinking, replace it. Just about any monitor repair, especially if you need to play someone for it, is not worth it. 19" LCDs are selling for around $100 these days.