MONITOR not displaying anything after motherboard exchange

Hii All,

Yesterday, I bought a new MSI motherboard.
New mother board is compatible with my old processor. but, after I connect all the cables, I find no display on the screen. It is complete blank. Even the “NO Signal” RED light does not turn to Green.

But, the Fans are rotating, casing front panel showing lights, hard disks making regular /usual noise.

Never had this problem, any idea why it’s happening? Did I miss something? I only removed the old mother board and
placed new one, since both same form factor and nearly same dimensions, it got set properly, just no display. Any Idea?

Please advice as soon as you can!

I am dying without my PC running.

Thanks