Dual Monitor Madness

So after building my first PC ever (w00t), I've ran into my first problem. For some reason I'm unable to get dual monitors working properly. The problem is when I click the "extend my desktop onto this monitor" box, my display is still blank. The monitor goes from standby to active once the box is checked. I can even scroll my mouse across the screen and watch it disappear into darkness, but there is no picture. Now I know the monitor is working because when I turn it off and back on the Acer logo appears for about 2 seconds before going blank. I'm attempting to power both monitors on an EVGA GTX 260 which is capable of dual displays. I've also updated the drivers to their latest. Has anyone had this problem before or does anyone have a solution?

You were right,iIt was a bad cable. I switched the DVI cable from the working monitor to the monitor that was originally blank and I'm having no problems with it as I type this reply right now. Probably should have checked that early but after building and installing and updating everything I was drained. Thanks for help.