Well, the company and brand of the "economic DVR" was of no help at all, (no instructional CD, no phone number, no helpful website or contact info) (≧∇≦）but with a friend we were able to get it working again. The monitor's MENU button was broken, which I hadn't realized, but we connected it to my computer with a LAN cable (I bought a male-male USB cable specially to connect it to my computer with, which didn't work, but my friend suggested the LAN cable which did). Still couldn't get the menu up there, but somehow that's when my friend realized the (old,freebie) monitor's buttons weren't working. So we hooked it up to a different TV monitor I had here and played with the buttons on the DVR and got the menu back, and I was able to reset the video quality back to 1080 in settings and got the picture back. Whew. Thanks for your help, though.
PSA: don't set your video quality high if you don't know your machine can handle it! You could lose your picture and all control. (^ ^)