@Shakaali: There is an old article somewhere on en.chessbase.com that describes Kasparov collaborating with the founders of Chessbase on the first version back in the late 1980s. He helped them come up with desirable features and was their main alpha tester.
You probably mean this (the same as linked by wayne_thomas) one. I've seen it before but it was interesting to read it again. Few interesting quotes:
"I had played a 'simul' against the Hamburg team and lost, mainly because I was tired. I hadn't studied the players, who were pretty good, including a grandmaster, and I got into terrible time pressure. I swore to avenge my defeat."
and later
"Kasparov spent two days preparing for the opponents, on an early Atari ST with 512 kilobytes of memory and no hard drive. With the home prep the clock simul went differently: Kasparov crushed his opponents 7:1."
So here you have it - Kasparov began using databases because he lost a simul.
However, I would be especially interested to find information about when Kasparov began using chess engines to assist his opening analysis. I guess this would first be mainly for blunder check but gradually the engines became strong enough to also find new ideas. I know that the amazing novelty in game 10 of 1995 WCH match against Anand was initially found by a computer but I assume Kasparov had been using them before that.
@Shakaali: There is an old article somewhere on en.chessbase.com that describes Kasparov collaborating with the founders of Chessbase on the first version back in the late 1980s. He helped them come up with desirable features and was their main alpha tester.
Here's the article quoting from Kasparov's book Child of Change.
https://web.archive.org/web/20130316145158/http://en.chessbase.com/Home/TabId/211/PostId/4007229