You would first need to remove the Tivo encryption and render the file as a plain .mpg file.
Otherwise, your friend will have to install Tivo Desktop on his computer and you will have to give him your Media Access Key.
There are several methods available to strip the Tivo encryption.
PyTivo and kmttg (search this forum) can automatically strip the encryption in the process of downloading from the Tivo to give you a plain .mpg file.
Since you have already downloaded this TV show to your computer, I would recommend using VideoReDo. They offer a 15 day free trial when you register for a trial key. You will be able to edit out the commercials and save as an .mpg file that your friend would be able to play on any computer.