Windows 1.0 was the first release of the Microsoft Windows environment for MS-DOS. It was not a commercial success, however its design would influence the Presentation Manager for OS/2.
Windows 1.0 did not have overlapping windows, and it did not support PS/2 mice. It only ran in real mode. Needless to say this was *NOT* a popular version. It really only is of historical interest.
Even in a primitive state like this, it did have all of the components such as, USER, GDI, KERNEL etc..
There is an excellent article on the development of Windows 1.0 here.