I have been having this same issue since I purchased my Acer over a year ago. First let me give the details to my PC, Monitor and software to help you help me
My PC is an Acer AM5100 with a quad core processor, AMD Phenom 9500, ATI Radeon graphics and I am running the Vista software. My Monitor is also an Acer monitor.
Now that those particulars are out of the way let me get to the issue. I can be working on anything, browsing the net, working in OneNote, listening to music etc. and suddenly my monitor goes black yet does not go into standby mode, the blue on light remains lit, my PC continues running but yet no matter what I do I can never see what is on my screen unless I restart the computer. I was advised when I called Acer a year ago that it was a software issue and that some software on my computer was causing this error. I had to restore to factory defaults at that time and one by one I installed software and waited and nothing happened so a few days later I would install the next etc. and I continued this tedious task until my computer was back to normal. I completed system back ups just in case and went on about my business but then shortly down the road the issue came up again. It has been a year, over a year, and this continues to happen. Over and over again, no matter how many times I retore to the beginning, no matter what software I remove or put back on. I have to believe that I am not going to have to restore my computer every time this happens please tell me there is a way to find out why this keeps happening and correct it once and for all. I'm very sad and frustrated. Please HELP!!!!!!!!!!!!