Here is what I noticed:
on my motherboard, there are 3 black slots and 3 pink, alternating like (Black, Pink, Black, Pink, Black, Pink).
My old RAM was in the pink slot.
I did what you suggested and remove the old RAM and replace with new RAM.
Everything booted up normally.
I also just tried to add back the old RAM into the black slot and now everything works.
I guess problem is solved but anyone why it worked in the pink slot rather than black?
Thanks everyone for the help!