This is a horror novel I read about 15 years ago. I’d say it probably was published in the 80’s or 90’s.
The plot was about a bright boy who had a talking computer friend (had some sort of clever acronym for a name I’m sure, maybe CAL? CHIPS?) that he spent a lot of time with. I think his parents were separated which is why he spent time with the computer.
The computer turns evil somehow and plots to kill the boy. Eventually his estranged father helps save them and I think everyone gets back together.
I’m pretty sure it was a small paperback all in black and I think the boy was screaming on the front cover. I desperately need to know this book!