Shorting the correct pins should have done it. If it's still not turning on then u may have another issue. If try unplugging power cord, then press and hold power button down for like 30 seconds (assuming ur power switch cable is connected properly) or short those two pins and keep them shorted together for 30 seconds) then plug it all back in and try again. If the same thing, then if you're motherboard is newer it may have the little led indicators on startup to show u that it's checking the ram, CPU, gpu, bios, etc. Look and see if it's stopping or giving a solid red led on anything. And if u have another power supply to try, u can try that. What type of system is it anyway? Good luck!