According to various reports, including website xboxevolved, it all starts with some glitchy visuals that require a reboot and, after you’ll reboot, you’ll only get the following message: “System error. Contact Xbox Customer Support” and below that you’re announced that an error 74 encountered.
This is not a brand new problem, as similar errors were reported in the past, but only now they became “popular” since lots of forum users are reporting the same error 74 on their Xbox 360 consoles. There is no certain information regarding the thing that triggers the problem, but some users seem to believe that it might be a problematic game disc involved.