hey there i have had this problem i have fixed it :-) it only cost 20cents ... :-)
the problem with mine was no vid,no audio, cant geting to safe mode, takes discs blue light blinks but thning else....
the way i fixed it was open the unit remove rom,power,card reader ... you see the preasure plates for the GPU and the CPU take them off and put a coin (about 1.2mm thick)one coin in the middle where the preasure plate will go for both gpu and cpu... put it all back together push start and it will work... it worked for me ... really you need to reflow the gpu... green light means video yellow means cpu :-)
The gpu is coming away from the main board is the problem with mine :-)
hope this helps :-) i would say if you have it this far appart just change the thermo paste while your at it.....
post something on here if this helps you :-)
best thing about this fix is you dont blast it with heat to fix it...