Karen,
it's easy to say "Don't Nag" but when every single thing is a fight, nagging happens. I guess chasing them with a big stick might work better.
My older son proved to us that bribes and punishments don't always work either. Kids can be pretty tough...

Lisa, we severely limited computer time with our sons, fortunately, it was still the days of dial ups and only 1 computer in the house. We didn't have the TV on much either. Younger son sold his gameboy in disgust because at 30 minutes of play time a day; he couldn't get good enough at any of the games to compete with his friends (snort )
The zombie appearance had to do with the fact that he suddenly realized the effect that he was having on others wasn't so good (he was an annoying little brat) and so he turned it all off in an attempt to fit in.
When he was old enough to take college classes, he took ASL (American Sign Language) which I think really saved his personality. You can't communicate without words and without expression.
When we saw the first video of him (actually telling a joke in ASL) we were in tears because he was so beautiful and animated again!