There’s no doubt that computers are fast becoming a major part of education and are infinitely useful for research, design, and communication.
In the UK today, 62% of children own a laptop, but, worryingly, the Daily Mail has reported that children spend on average 12.6 hours a week online but only 4 hours doing sporting activities. (http://www.dailymail.co.uk/sciencetech/article-1352361/Children-spend-time-computers-TV-exercising-week.html
A government report of children in school years 6, 9 and 11 found that just 1-2 hours of this time per week is being spent doing school work, which suggests that the remaining time spent using computers is spent on online games and social networks, such as Facebook. (https://www.education.gov.uk/publications/eOrderingDownload/RR672.pdf)
The same report stated that the use of computers at school and/or at home only improved certain subjects at certain levels, dependent on the Key Stage that the children were in. That being said, there are reports that ‘Brain Training’ computer games can improve children’s school grades and boost their IQ.
Another criticism is that the increase in computer and TV usage is a major contributing factor to the rise in childhood obesity as children are becoming less and less physical. The NHS have reported that 2 million children in the UK are overweight, 700,000 of which are obese. As with everything in life, moderation is key with computer usage.