my E-machine could not power on !

[disinfo]

No, not playing see this site for reference;

http://www.helpwithpcs.com/courses/power-supply-basics-inc-pinouts.htm

Your green wire is PS_ON

Shorting PS_ON to ground should have the effect of starting the PSU, if not its probably dead.

 

[Softus]

Well, you might have f***ed that PSU then.

 

[Igorian]

Take the advice. Bin it.