Bios problem leading to Bricking ASUS G73JH-A1

I had recently purchased an Asus G73JH-A1 online and after a month maybe more was able to recieve it finally, everything was fine for a few days but one day suddenly i wanted to switch on my laptop and when i switched it on nothing happened and no display on the screen not even the asus logo at the beginning and i had to take the laptop to the asus global service centre here in the Dubai and after a day they fixed the problem and told me that it happened because of my Bios configuration but i had done nothing except install games and few software such as VLC media player.
After i went to the guys at the service center they told me that there is a problem with the motherboard because the laptop is working properly for the time being but there will be no sound and i could only use headphones and they told me that they have ordered a new motherboard but it will take atime maybe 3 to 4 weeks so i took the laptop with me back to my home and everything was okay when i noticed that the keyboard lights were not working and then i came online read lots of threads and come to know that this problem mainly happens because of upgrading the Bios to 206 and that was what the people at the asus service center had done and so i again went online and after reading a few threads in various forums on the problem of the keyboard lights i came to the conclusion that if i could roll back to my original Bios (204) then atleast the lights would come back again, so i tried to roll back to the Bios 204 by restarting the laptop and hitting F2 to take me into the Bios menu from where i rolled back to the Bios 204 which i had downloaded via Asus website but after installing the bios when i restarted the laptop the same thing happened again and the computer totally bricked with nothing on the screen.
I took the laptop again to the service centre and had the technicians check it out and they told me that they cannot fix it because of a faulty motherboard but i told them that when earlier this same thing happened they were able to fix it and they told me that by removing the RAM totally a switch can be found which after pusing it will reset the Bios to factory default but now it was not helpful so now i am waiting for a new motherboard replacement for nearly 3 weeks now.
I just want to know whether anybody can tell me what the exact nature of my problem is because when these guys at the service center told me that there will be no sound from the speakers because of a faulty motherboard i was not convinced so after hours of long thread reading i uninstalled the total Creative programmes and i got the speakers to work properly and also had the problem of the computer freezing up fixed.
Can someone please help me as to whether it is really faulty motherboard or BIOS problems or maybe VBIOS or maybe a faulty GPU or something else.