Dual monitor setup with identical monitors - why do the monitors look different?

I set up a laptop w/a docking station, keyboard, & 2 identical monitors such that when the laptop is closed, I can work off of the 2 monitors. However, despite the monitors being the same model, they have different recommended resolutions. When I go with those, one of the monitors shows everything as larger/more "zoomed in" than the other. But if I change the resolution, everything on that monitor gets slightly blurry.

The laptop is Windows 7. The monitors are Dell E1916H. The docking station is Dell E-Port Plus Model PR02X.

When I right-click on the desktop and hit "screen resolution," this is what I see:

-For the "good" monitor, the "Display" drop-down says DELL E1916H and the "Resolution" drop-down says "1366 x 768 (recommended)." The "Multiple displays" drop-down says "Extend desktop to this display," and it states "This is currently your main display." This monitor is connected to the docking station w/a DP cable.

-The "problem" monitor says "Non-PnP" in the "Display" drop-down. (I'm not sure why it wouldn't say E1916H like the other one.) The "Resolution" drop-down says "1024 x 768 (recommended)." The "Multiple displays" drop-down says "Extend desktop to this display." There is a checkbox for "Make this my main display" that is currently not checked. This monitor is connected via a VGA cable.

How can I get the second monitor to look like the first one? The only difference I can think of between the two is that they're connected with different cables.

Thank you!