Thanks for the info. I'd still try my suggestion of trying a different monitor.  Could also try a different connection via USB adapter. Overall, I think the monitor is toast, as it is from 2012.  There's generally no fix for bad monitors.
Hi. Posted below is a picture of the U2212HM. I can see part of the PC (Optiplex 780) in the top left of the screen, otherwise, all that's visible are colored lines and cracks, but when it is turned off, it looks fine. Please help! [IMAGE]
U2212HM, colored lines and cracks