Can't install win32gui

Install pywin32. That gives you win32gui.

pip install pywin32

Win32gui isn't compatible with 3.7.

3.7 was realeased in 2018 and the latest version of win32gui was released in August 2017.

I would suggest installing 3.6 or lower as a workaround.

EDIT:

The answer by @bronson beat me to it by 9 days, but installing pywin32 with pip install pywin32 will install win32gui alongside modules for interfacing with windows.