1 red light

The cause of E-74 with one red light Error might be overheating of your console and for avoiding such error in future you need to put your machine at an open space. Ensure that it is placed near the window or you can also make some external arrangement for cooling of console such as cooling the machine through a pedestal fan.
But as your Xbox already have E74 with one red light Problem which can be solved by only repairing it, no other alternative.
Either you can send your Xbox to Microsoft (Please note that microsoft is no longer providing extended warranty for E74 with one red lightError) and wait for 3-4 weeks. If you don't want to wait for a month, you can also fix E74 with one red light problem with the help of this DIY Video, the guide will explain step by step approach to fix the problem. Choice is yours.



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You can check out the informative blog post at http://www.fix-xbox360.info/2008/09/11/xbox-360-disc-read-error-e74-error-no-video-problem/
This post describes the E74 error with one red light problem.

hope it helps...