Chosen Solution
When turned on, power button is green then goes to red blinking 25 times while fan sounds like it’s at max rpm and it begins loading xbox logo on screen but then screen goes blank before system shuts off again. Cleaned fan and heatsink and replaced thermal compound but problem persists. Any ideas? I suspect a possible GPU solder issue but haven’t seen that problem behave this way before. Thanks!
Check your hard drive connection, This is known to happen when it is not connected properly. Microsoft fixed the GPU solder issue in the Xbox 360 S.
