I just bought a used Mac Mini and upgraded it (professionally) to 2GB. It came with a cheap Westinghouse monitor. However, when I turn it on, the monitor says "No Signal Input" and goes to sleep. I turn my computer off and on (with the power switch as I can't see what I'm doing), the picture has come back once (picture is fine) but that's it. When I restarted, it went back to "No Signal Input". I've used a DVI cable, and a DVI to VGA adapter and a VGA cable (the monitor takes both). I have gotten it to work once with each cable. What gives? EDIT: I tried another monitor with the same result. Also, when I was able to make it work, it would not let me adjust the volume. In Preferences>Sound, the sliders were grayed out. When I put in a CD or attempted to play something from iTunes, it wouldn't play it. The time bar stayed at 0:00 (as I had no sound anyway). It worked before with the same speakers I'm using plugged into the headphone jack. ???