Xbox 360. got an error

All four lights means there is a problem with the av cables, check to make sure they are in all the way, but that is inconsistent with the E79 error, which is a hard drive error. Check the cables, then try running your machine without the hard drive. If all else fails, or if the hard drive is bad and under warranty, call 18004myxbox and get it fixed. If you need to send it out and will cost $ ask to speak to a supervisor, and they can usually get the cost down a bit. Good luck.