CW Skimmer & Flex / Replaced Dual Monitor with a New Curved Monitor

The X and Y position of the CW Skimmer window is remembered and much probably now it is out of the range of the new monitor.
I'm not sure if you can easily edit some Skimmer related file/register to reset the coordinates.

If not, try the following: (no success guaranteed)

Reset Individual Application WindowsIf a specific application window is in an undesirable location (e.g., off-screen), you can use a built-in Windows trick:

1. Hold down the Shift key and right-click on the application's icon in the taskbar. (If the window is maximized, first click "Restore".)
2. From the classic context menu, select Move.
3. Press any arrow key on your keyboard once to activate the move function.
4. Move your mouse (without clicking any buttons) to bring the window back onto your visible screen.
5. Click once or press the Enter key to drop the window in its new position. 

Alternatively, holding down the Ctrl key while closing an individual window can sometimes reset its next opening position to the default, provided the application supports this function. 

If you get no answers or help I can install Skimmer and search for the registry keys

If you are in rush and still have it, reconnect a second monitor and move the Skimmer window to the curved.

Possibly other applications can have the same issue.