With four red lights on around the power button and the console reading the error message E66, the problem may be with the DVD model or the firmware. Fixing Xbox E66 error will require doing the following steps.
Steps in Fixing E66 Error
1.Firstly restart to make sure the error is not another fluke by unplugging all the cords and devices attached to the Xbox 360 console and reattaching them.
2.Turn off the 360 console and disconnect the hard drive by pulling the latch on the front to detach it easily. Check the console by turning on without the hard drive first and with the hard drive again. This will help find out if the error is related to the drive or not.
3.If this does not fix the problem, check the DVD model or version number to see whether it is the one required by the dashboard or not. Also check the firmware version to see if it’s compatible with the number required by the dashboard. Make sure the version of the DVD drive is same as required by the dashboard and also check whether it is using the original version of the firmware or a newer version.
4.If the dashboard can still be accessed, run the Xbox Live update by connecting through the Internet to download the version compatibility fixes.
If doing any of the steps in fixing Xbox E66 error does not do any good, consult the xbox 360 repair guide or send it back to Microsoft for repair.
While error codes aren’t really a big deal, if you have xbox 360 red ring of death, then you will definitely need some serious help. Yes, you could send it to Microsoft for a fix, but it will cost you hundreds of dollars and you will have to wait at least 5-6 weeks. It’s a much smarter idea to do everything yourself although the warranty might be voided.