i just came back from sim lim after collecting my com. my prediction was right. i still cant on my bloody fking com!

after changing new casing 2 times, psu 2 times, ram and HDD, i still cant on!
Motherboard is tested ok at warranty site, gcard is ok too cos at sim lim can on, home cannot.

wtf is wrong?!?!?! i still can't figure out.. it isnt the power supply in my house cos i still can on the fan and TV, i also tried bringing the cpu to my living room use the power unit there, still it does not work.

Why Sim Lim can on?!?! anyone help me plsss... im at my wits end..