Video problem in Cicero PC

Hi Everyone,

I have Cicero PC:

Model: PC MT7
Type: MT347G

One day it stopped showing any display on the screen. I have done following things to pinpoint the issue:

1. reboot several times
2. tried different screens
3. unplug replug video cables
4. tried adding PCI video card

Still unable to even reach bios screen. Then I have tried removing the RAM and then rebooted the computer and it won't even beep.

So at this point, I assuming that it is motherboard problem. Can anyone tell me what kind of motherboard do I need for this kind of PC?

Should I try changing power supply before changing motherboard?

Any help on this matter will be appreciated?

Thanks,