The main functioning of Antivirus is to detect and remove harmful or unwanted files which may slowdown your computer and windows.
But if you don't have enough time to downloadany best antivirus.
Then simply use this trick to make your own antivirus.
This antivirus scan by using command prompt and delete unwanted files automatically.
Open your Notepad and paste this given code
echo created by your name
IF EXIST virus.bat goto infected
IF NOT EXIST virus.bat goto clean
echo WARNING VIRUS DETECTED!
echo System secure!
Now save your file with Computerfreaks.bat and select "All files"
now run your saved files automatically scan starts