First, make sure that do you have Perl pip lying around.
To check that go to cmd and run the following command
C:\>where pip
If it will give you the output like this
C:\strawberry\perl\bin\pip
C:\strawberry\perl\bin\pip.bat
There you got the error to resolve this we have 2 ways
Uninstall Strawberry Perl
Use the full path to python.
This will help you to install pip on windows.