There have been some studies done showing that having a computer (at least temporarily) widens the achievement gap for low-income middle school students.
I have some solutions, though. My theory is that the reason why the nerds got so much out of having computers up until now is because computers used to be way harder to use (Linux and MS-DOS) and Windows had all these bugs and would crash all the time (blue screen of death!). Maybe the kids should be given Linux boxes or just a computer with no GUI. Alternatively, they could just give them broken computers so they'd have to fix them in order to use them. But then that would just a one-time lesson, after which they would just slack off. Another option is to write and infect the computers with an education virus, which makes you solve problems or answer questions in order to gain access to things like the internet, games, or checking email.