If your Xbox 360 fell victim to the E74 error and you paid Microsoft for the repair, you should have received a refund check back from the company by today. If you paid for a repair and have yet to receive a check, you'll need to follow up with Microsoft before the hard deadline of November 1, 2009. After that ... well, you're just going to have to eat it.
The E74 error was placed under a similar warranty to that of the Xbox 360's "Red Ring of Death," after data revealed it was another widespread defect for the console.
[Thanks, Matt L]