OK.. thank you all guys. especially estel who explained a lot of things to me.

Now my current plan is to buy another n900 in cheap price.. I have found one. need to contact the seller if he still has it or not.. and check if everything in the bottom half works fine.. then replace the board with my n900 and sell the damaged one in quite reasonable price stating usb charging doesnt work.. and putting some attractive offers like extra battery and external charger.

I guess I need to cancel the crappy pcb from china. As estel said, I cant go on soldering each and every stuffs in the pcb. or if it cant be cancelled then wait for it to arrive and see it... (maybe loss of some good money).