Evilspeak (1981)

Evilspeak is a 1981 American horror film directed by Eric Weston and starring Clint Howard.

It is about an army cadet who is bullied at a school, and he uses demonic forces on a computer, in order to gain his bloody revenge.

Plot
During the Dark Ages, Satanic leader Father Lorenzo Esteban and his followers are approached by a church official on the shore of Spain, telling them that they are banished from Spain and denied God's grace unless they renounce Satan and their evil ways.

Trivia
It was listed as a "video nasty" in the UK, and therefore banned.