Dell P2311H Stuck in Power Saving Mode

Howdy,

I have a Dell P2311H monitor that I bought a few years ago and everything was working perfectly until just recently when I upgraded my desktop computer (non-Dell, I built it myself). I have a dual monitor setup and my P2311H has lost signal and now only stays in its Power Saving Mode. When I press the Menu button it tells me that there's no signal and to press a button or move the mouse. It's acting like there is no signal coming into the monitor through the DVI cable, but there is a signal because my other monitor works on all of the DVI ports. 

Troubleshooting Performed:

• I've been looking at other posts on forums and none of them have been helpful because it seems like the solution to their issues is something simple. I know it's not a loose DVI cable or power cord. 
• I know definitively that it's not the video card because my other monitor works in both of the DVI ports.
• I know it's not the cable because I've tried using another working DVI cable from my other monitor. 
• I've also tried using integrated graphics on my motherboard and that doesn't work either. 
• I've even tried the monitor on multiple computers and multiple video cards and it still will not receive any signal. 
• I've tried holding the power button for 5 seconds, but nothing happens.
• I've tried holding the 1 & 4 button to get the diagnostics menu, but it will not come up. The only menu I can get to is the Input Selection Menu for Auto, VGA, or DVI, but changing those has no effect on the monitor. 
• It is not a sleep issue with my computer because my computer is fully functional and works perfectly with my other monitor.
   

Here's my system:

Dell P2311H 23" monitor
Windows 7 Ultimate 64-bit
Intel Core i5-3570K
NVIDIA Geforce GTX 560 Ti
ASUS P8Z77-V Mobo

Thanks!