The best would be to replace it with decent quality PSU instead of investing your time and money into piece of junk. Crap PSU have significant chance damaging computer hardware and they are inefficient. Usually price difference between crap and good PSU will turn the other way around when counting electricity cost difference over computer lifetime, so you will pay more instead of saving. You may think that power consumption difference of something like 20W is nothing, but say when used for 8 hours a day, it's 58 kWh per year, multiply by 23.8 euro cents per kWh and it's 14 Euro annually. Not to say they also usually have poor standby PSU efficiency as well which adds up as well.