Did not have E75 error but quit working!

Can you please unplug the power supply from the wall and the back of the console for 1 minute, and they try again? Also check the color of the power supply light.

I know this sounds stupid but i have know this to happen... have you checked all the power cables are connected also is the light on from the power brick? If not your problem may be the power brick (Fuse blown etc)

If not that does the xbox make any signs it may be getting power to it (For example if you are playing on a HDTV the "No signal" message disappears)

This is what E75 is:

Overheating is the culprit- as the Xbox 360 does not have a particularly powerful cooling system, and has a cramped case, levels of heat inside your console rise quickly. Over time this excessive heat causes damage to the video scaler chip and graphics system, leading to malfunctions and eventually the e75 Xbox error. Basicly your xbox was not getting enough airflow and the motherboard flexed over and over again causing a cracked soder joint somewhere....

Although it may not be fixable if you are not under warranty (assuming you have an older generation of xbox 360) then I recromend just getting a Xbox 360 Slim because if Your xbox 360 not under warranty you will have to spend quite a bit of money to fix your it and even if Microsoft  cant fix the xbox 360 then they send back a refubished one that will most likely red ring as well My recromendation is to just get the Xbox 360 slim because it runs WAY better than the xbox 360 original. Also do not open your Xbox 360 you will lose any way to have microsoft fix the console and if they find out that the console was tampered with than they will console ban you from xbox live for "System Tampering"

From what this sounds like check your power brick it should be yellow when the xbox is not on and when the xbox is on it should be green. if it is RED than call xbox support.

Hopes this helps in some way.....

-Sager