Windows can be installed on Android phones. This is how as per by Android Blog.

1. Download aDosBox zipped file from Android DosBox and install it to Android.

2. Download Windows 3.1 ISO or Setup files and install it on Android phone by any of the following 2 methods:

METHOD1
i) Extract Win3.1 setup files on the SD Card in a folder called “winsetupfiles” and mount it to Android.
ii) Make a folder on SD Card by the name “windows”.
iii) Open up aDosBox on Android and perform the following steps in sequential order:

*Type the command
mount d /sdcard/winsetupfiles
This command will mount your setup files to a virtual “D” drive.

*Type now
mount c /sdcard/windows
This command will mount the filesystem to install to.

*Type
D:
This changes your directory to the D Drive which contains our setup files for Windows 3.1.

*Run setup file by executing below command
setup
Now follow the onscreen steps to install 3.1 on your device.

METHOD 2
Install Windows 3.1 on PC and then copy to Android.
Install DosBox for PC and extract all your Setup files for Windows 3.1 in a folder on your C drive. (say, you did in C:/win32).

*Run DosBox and type:
mount c c:/win32

*Now type:
C:

*Now type
setup
The setup will run. Follow the instructions. Install Windows 3.1 on c:/windows.
Once its installed, Close DosBox, and navigate to your freshly installed copy of win3.1. Copy the entire “windows” folder on to your SD Card.

Run Win 3.1
Open up aDosBox on your device.
*Type
mount c /sdcard/windows

*Now type
C:

*We run Win 3.1 by typing in:
win.com

Finally, you should see your Windows 3.1 splash screen.
Congrats, you are now running Windows 3.1 on Android.