Computers provide fun not learning. If there are any benefits, they are due to changes in teachers style. Computers reduce the opportunity to develop manipulative skills. Visual stimulation is not the main route to non-verbal learning. Difficult to train teachers adequately.
Computers break down.
There are problems with technical support, especially in primary schools. Computers distract students from the lesson at hand. Computerised education is driven by the self-interest of industry. Children need a broad base not a one-dimensional computer. Computers discourage children from linking ideas.