Step Into the 80's! (TV story)

Prime Computer advertisement was a video released in 1979 to accompany the marketing campaign to sell Prime computers. It featured Tom Baker as the Fourth Doctor and Lalla Ward as Romana II, and was licensed by the BBC. There were 4 parts.

Part 1
The Doctor and Romana use their Prime Computer to calcute the orbital coordinates of 900 planets in the constellation of Kasterborus to stop the end of the universe.

Part 2
The Doctor enters his TARDIS to discover that Romana redecorated the interior and added a Prime Computer. The Doctor says that he has already seen one on Gallifrey in the constellation of Kasterborus. The sentient computer tells answers to the Doctor that his scarf is 7.013 meters long excluding loose threads and

Dr.Who meets his match
The computer tells the Doctor to marry Romana.

Dr.Who and the Aliens
Aliens from Liprogopolis kidnapped Romana so that Dr.Who tells them where to buy a Prime Computer.

Cast

 * Fourth Doctor - Tom Baker
 * Romana - Lalla Ward
 * Liprogopolis alien - unknown

Home video releases
They were released commercially on DVD with Destiny of the Daleks.