Red rings of death on my xbox 360 I need to know how to fix it

The red rings can be caused by any number of things from a faulty power pack on the suppply cord to a loose av cable from back of x box. but the main cause of the "Red Ring of Death" is overheating. On the main pcb inside the xbox, you will see 1 or 2 small micoprocessors,
depending on when u bought ur box and what version it is,
when the unit heats up the pcb bends causing the processors to lift off the board and loose contact, you can either try mounting the pcb at diff points so it doesnt bend, or the longer term fix is apply some extra heat sink compound between the processor and the pcb and re solder the processor to the pcb. anyway. good luck.