Can't load pywin32 library win32gui

This works:

import pywintypes
#import pythoncom # Uncomment this if some other DLL load will fail
import win32gui

I had the same issue. I added the path where pywintypes34.dll to system path and it worked.

In my case it was C:\Python34\Lib\site-packages\pywin32_system32

My guess is that win32gui depends on some DLL that is not on your system. You can download depends and see what you're missing.

However my first attempt will be try installing pywin32 from the installer, not by building it.