Just installed a driver for my second monitor and something happened to my main monitor

[KrustyKrab 1]

I bought a tiny touch screen 7 inch monitor as my second display. Everything was plug and play, except for the touch screen functionality at fist. There were no issues with using the two together.

 

I downloaded and installed a customised driver from a developer who made one specifically based on my rig, then after rebooting my computer again my screen main display looked like this on the Login page (see attached photo).

It is basically the size of the 7 inch monitor on my main display. Once I've logged in, everything is actually fine.

 

I've tried uninstalling the driver and even completely unplugged my 7 inch second monitor, and it still didn't fix the issue.

While there are no issues once I've logged in, I just don't want to be stuck with this Login screen as it's such an unpleasant sight for my 31.5 inch 4K monitor.

 

Any help would be much appreciated!