"Electric Dreams" is one of my all-time favorite movies. It came out
in the early 1980s, when people were first bringing into their homes
these new personal computers: there is a great scene in the movie
when he is picking out a computer and there is prominently displayed
in the background an Apple IIe box, IIRC.
The movie has a strange fear of technology message to it, much like
Wargames as Marcus mentioned.
Unfortunately, it is utterly and completely out of print and not
available on DVD. My copy on VHS was recorded at a weird speed and
plays back only on my wife's old TV/VCR combo. Time to digitize ;)