As the burden of maintaining computers, networks and other equipment often fell on the IT co-ordinator, who usually had a full teaching load as well, the report said systems or devices were left unusable "simply because there was no immediate help available".
Teachers' lack of access to computers, and their inability to access school networks from home, were also highlighted by the study.
Concerns about ICT support were echoed in a new report from Japonite (the Joint Advisory Panel on Information Technology), which warned that technical staff had to be paid higher salaries and treated more like teachers to end the recruitment crisis.
It quoted a Department for Education and skills official, who described the situation as a "major problem". Even measuring its scale is made difficult by a lack of data.
The panel, which included the British Computer Society and the e-skills National Training Organisation, said technical support must be regarded as a new profession straddling both education and ICT, with its own professional body and qualifications.
Technicians should be regarded as a source of competent IT teachers, the report said. Salaries also needed to rise, as even the highest-paid earned pound;5,000 to pound;10,000 less than their counterparts in industry.
Schools must realise that at between two and four per cent of budgets, the cost of technical support was greater than that of hardware and software.
The DFES has been consulting with industry on ways to improve technical support for schools and plans next month to release guidelines to help schools employ staff with the right skills. A "constructive discussion" has been held with firms on the need for dedicated help desks for schools and the cost of technical support.