System not powering up

System not powering up 
If your system isn't powering up, the first thing you should try is to make sure all the connectors are plugged in. If that doesn't work then try the following:

(1) Make sure the connection between the power supply connector on the back of the system is securely in place by gently pulling on it to make sure that it's fully locked in place in back of the Xbox 360.

(2) Make sure that the cord connecting the power supply to the outlet is firmly in place by pushing firmly on the connector to make sure it's all the way in.

(3) If you're connecting your system directly to a power outlet, make sure the power strip is ON and functioning. More expensive surge protectors have breakers or fuses that may be triggered during a power spike, so make sure those are in order. If your surge protector has a fuse, check it by removing it and looking through the clear window. There should be no burn marks inside the glass and you should see no breaks in the filament. If you see any burn marks or the filament is broken, replace the fuse in the surge protector with a new one.

(4) Ensure that you're connected into a properly grounded outlet. While the Xbox 360 should work without proper grounding, doing so could damage your system and it's not recommended.

(5) One final step is to check all the pins and cables on your connectors. While both are fairly well protected, sometimes the plastic can become brittle and more often Fido makes a new chew toy out of your $30 cables. If your cables are damaged, your best bet is to simply purchase new ones. You can purchase new AV cables from your local game store. If you need a new power cable, be prepared to pay Microsoft a pretty penny for it. If you’re crafty with a file, you just file off that annoying bump on the power supply, in which case any ordinary $3 computer cable will work.