sorry, i am not pretty sure

problem. before i also had the simular problem. every time before i want to open a vedio clip, i have to open the media-player first, not just just click on icon of the file, otherwise the systme will reboot automaticly.
it seems the vedio card driver crashs with the I/O. Just try find the new version driver from the producer. It might be the solution for this kind of problem.