You can activate your virtualenv and then start server using a bat file.
Copy this script in to a file and save it with .bat extension (eg. runserver.bat)
@echo off
cmd /k "cd /d C:\Users\Admin\Desktop\venv\Scripts & activate & cd /d C:\Users\Admin\Desktop\helloworld & python manage.py runserver"
Then you can just run this bat file (just double click) to start the server