Guys, need help here!

I am from Penang and am looking for someone/some shop that can repair XBOX360 asap!

I bought it about 6 mths ago at Prangin mall ACE electronics, and i seldom play. one day i turn it on and just played for 5 mins, then the system hang (screen freeze with funny noise and sytem hang)... tried turning on/off, plug/unplug power, on with/without game disc.... still hang after 1 to 5 mins everytime i turn it on

so i return it to ACE ELEC for repair.. and now it has been 3 weeks still not ok yet, everytime i call they say its the motherboard issue and take time to repair... I mean i have some trust in them as i have been buying consoles and games from them all the while, but i guess perhaps they are not good at repairing this.

thus any recommendation would be much appreciated!