Do you got a Red Ring of Death (ROD) ?
Send it to MS. They will do a Reflow on the Mainboard.
The best about sending it in: Even if your box is flashed they will repair it, as long as your box has still the security label inside.
If you dont have a label, you can get one from the 'usual places'.
MS will send you the box back and it will still play all your stuff.
As mentioned your box is bulletproof for 2/3-years because of the MS-Guaranty/Warranty.
True, but the quality of the boxes seems to be randomly wide-spread from low to high Manufacturing-Quality.
Even the PS3 had/have problems with their BD-Drive and FW-Updates.
Who knows.
Greetings
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