>He is not young anymore and I have hard time trying to manage him. I am unable to be strict with him, so he does what he wants. How do you influence your kids?
Bad :)
Kidding aside, my kids are not really kids. One married and graduated, one in her final semesters, and the third is a seventh grader. And they all have their own computers - I kept buying them as early as I could.
Generally, I stayed away from imposing rules which I can't explain. A rule which doesn't have a clear goal and can't be eplained to a kid is under doubt. And then, I've always treated them as grownups, assuming they'd understand what I'm talking about. Simplified where needed, but always tried to get the substantial meaning across. And there weren't any stupid questions, nor "you won't understand that". No question would remain without an answer. OF course, my wife has the same attitude, sometimes even more radical than mine. And they all turned out great, to our pride and pleasure. All three are straight-A students (and the oldest one graduated summa cum laude).
As in your case of fighting over the keyboard rights, I'd try to work out a schedule, or take a nap until they get bored. I love it when they are curious, and wouldn't stand in their way of acquiring knowledge. I'd rather do what I already did: save on other things, and get them books, computers etc. And do my homework when they go to sleep.