Why does my monitor display a "Sync. Out of Range" error message?
Answer: This happens when your screen resolution is set to something higher than what your monitor can display. For example, if your monitor supports resolutions of up to 1024x768 and your video card allows you to crank it up to 1600x1200, doing so will give you an error. Another reason you might get the error is if the refresh rate you selected a certain resolution is higher than what your monitor supports. The monitor can't "sync" with the video card, so it just gives you that "Out of Range" error. If you are sure you have your resolution set at a reasonable amount, make sure that your monitor is plugged in all the way. Actually, if you're like me, that might be the first thing to check. =)
If you are using Windows, hold down the F8 key while the computer is starting up and choose "Safe Mode" from the list of options that appears on the screen. This should force the display to be a low enough resolution so that it will work. On a Mac, hold down the Shift key while booting up to start with extensions off, and that will usually do the trick.