How much time should children spend on the computer, television and game systems

I only permit my 4 years old watch TV less than 15 minutes per day. Sometimes I just try another way to let him forget the TV. And every week he has about 20 minutes to play the computer. He is very interest in operate computer, like MSN, download some pictures or do some other things else. But for protecting his eyes, I need prohibit him to touch these things.

Hai hru doing, so you have asked good question so my in way children should spend maximum of two hours a day on the computer, television we can another one hour totaly children should spend maximum of three hours in electronic system if they spend more time on computer i think they will get more probelms its not right time spend more hours children on the computer or television. they are divine personalities so we should give right guidence to them. they have lot of time to do different works and commiments on computer isn't it? is it right from them.. give me message.