2713H using generic PNP monitor (not Dell) driver & not at native resolution

Monitor is connected to Dell DisplayLink via HDMI cable. I had everything working with the monitor running at native resolution, then the problem cropped up after I plugged the monitor into the laptop HDMI port directly. Now, I can't get the system to use the Dell driver and the driver installer won't re-install to force it back (see screenshot). (The monitor is connected via the DisplayLink when this is run.)

The following screenshot shows the current state of the resolution and monitor driver being used by the system. Previously, the exact same connections were working at native resolution and the monitor showed up as Dell P2713H, rather than "No Monitor" in the Screen Resolution control panel.

* What is the 20 digit alpha-numeric monitor serial number on the monitor label?
* What is the revision number on the monitor label (A00, A01, etc.) ?

* What specific computer model, desktop/laptop?
Dell 6430u
* What operating system?
Windows 7
* What video card?
Intel HD Graphics 4000 via USB 3.0 DisplayLink
* What video out ports are available on the video card?
DVI, HDMI
* What video out port are you using from the video card to what video in port on the monitor?
HDMI, HDMI

* What cable are you using to attach the video card to the monitor?
* Are you using the Dell supplied cable?
No - Monitor not supplied with HDMI cable
* Press the monitor Menu button to open the monitor OSD (On Screen Display). The bottom of that screen should show a resolution. That resolution should match the monitor default resolution
As noted, it does not. Monitor native resolution: 2560x1440, current resolution: 2048x1152.