The monitor isn't working. A 24" Apple cinema display monitor. It's connected up to a Mac Pro processor at the back, and has been working without issue since 2009. Yesterday, I turned on the power and the computer began to boot up, except the monitor didn't light up as it usually does. It flickered bright white for half a second, and then the screen blackened again. No matter what I do, I get no response from the monitor after that. I've tried tweaking wires, removing devices, switching power sources, and always get the same response. This happened yesterday, and after maybe 20 tries, the monitor eventually stuck, and it worked correctly for the rest of the day. Today, the issue returned. Again, after maybe 20 attempts at turning off and on the computer, the screen stuck, and now it's working again, for the moment. I would suggest that there is something wrong with one of the wires, or the monitor, but I think it could be something else. A few months ago I purchased a HP keyboard to use in lieu of the many **** Apple ones that were causing much grief. The HP one works correctly and I've had no problems. Like the Apple keyboard, the HP one has a feature that when you press F14 and F15, they control the brightness meters of the monitor. F14 brings the brightness down, and F15 brings the brightness up. The other day, I used F14 to bring it down fully, and after a few levels, the screen flickered and then shut off completely. There was nothing to do except turn off the computer; when I turned it back on, it was back to normal. But since then I was cautious using the brightness feature. It happened again a second time as well. I'm wondering if this could have something to do with how the monitor is behaving now. Maybe the 'apple script' that allows the feature to work is tampering with the monitors ability to work when the computer boots, or something. I'm fairly confident that it is not a hard ware issue, and has something to do with the script that tells the monitor when to turn on, and adjust the brightness levels. But I don't know, maybe it is hard ware related. In any case, this is a problem. I don't dare turn off my computer lest it doesn't turn back on. I can't afford to purchase new cables on the off-chance the problem is hard ware related. If there any way to determine if the issue is something to do with the script that tells the computer how to behave when it initially boots? I'm not sure what the problem is here, but I know it will persist unless I do something about it. Apologies for the long wall of text.