Re: Motherboard problem.
The very first thing to get help is post which model MSI motherboard it is.
If the motherboard has on-board graphics VGA socket, use that at first, instead of plug-in graphics adaptor.
Next thing is to remove all PCI cards. Make be sure the internal small speaker is present.
A good start-up is normally signalled by a single "beep", and if there is characteristic disk activity, it is the first sign that something lives. If you get any start-up screen texts, you know the processor is not dead, and the motherboard is basically functional. Even without any graphics, you can tell if it is totally dead or not.
For the symptoms you describe, it could just be the graphics adaptor. The SMPSU can also be missing one of its outputs. if you have an alternative graphics adaptor to try, as a test, that can be helpfull in figuring out what might be wrong.